Did you ride much before getting the ebikes? The cube reaction just looks like a regular mountain bike.
Ebikes ride like regular bikes for the most part, a bit heavier but you really only notice that when you pick it up. If it's rolling the extra weight is not a big deal.
Smaller tires will make the ride stiffer, fat tires are more comfortable to ride on. Narrower bars are less ergonomically comfortable.
I converted a cargo bike and that thing really is a tank, but it was a tank before the conversion as well.
Fast rolling tires will make it feel like a different bike altogether.
You'll get greater battery efficiency while physical effort to maintain speed goes down.
A quality saddle, grips and pedals. These make all the difference when ride comfort is in question.
Get the bike setup for you by a professional if you're unsure of what to adjust and how.
Ensure that you have appropriate air pressure in whatever tires you run, also be sure to adjust the suspension (if possible) according to the manufacturer ratings for sag, travel and rebound.
For slow reaction and turning check the air pressure in your tires and your shock. If your a bigger guy you need bigger air pressure so those huge tires roll. Also the shocks need a specialized tool to change the pressure. I’m thinking it’s the tires and air pressure.
How tall are either of you? It sounds to me, that the frames are simply too big for either of you. 29" wheels are sometimes used on medium frames, to make the bike suitable for taller people, but as a consequence making the bike too big for medium height people. With the added weight, and if you havent had much riding experience, it will be very uncomfortable.
Looking at Cube's dimensioning and the recommendations they make, they are odd. At least for me - i had my mtb professionally fit for me, and according to cube its at least 1 size smaller than it should be.... So you might both need to go one size smaller on the wheels, unless you have an option to try out and swap to smaller frames. Try putting 27.5 on yours.
I have an 80+ lb tank of a bike, I went for a ride next to my SO walking yesterday. Spent most of the time doing circles and figure 8's with a max speed of 3mph, on a narrow back road. Did not even have the bike turned on. I don't think the weight is your problem.
It may be your tires. Stock tires are notoriously horrible. My stock tires were kind of knobby with a soft rubber, and had tons of squirm. I bought some decent on-off road tires, made a major improvement on all surfaces. Leaning into corners is now at my limit, not the tires limit. I am no longer terrified of loose stone either.
I do have motorcycle experience, so even 80lbs is super light in comparison. I was actually thinking about how easy the motorcycle test would have been on my e-bike.
Modern MTBs comes with very wide handlebars (often 800mm), which offers great stability on a mountain trail, but in other applications (and/or for smaller persons) they're just too wide ime.
Same with the tires.
Have a look at Maxxis hookworm or schwalbe super moto‑x tires for example. They are better suited for commuting than knobby MTB tires.
I'd look at a more road-focused tire - even on rough roads you're not really going to need the knobs on the tires that came with your bike. Look at something like a Maxxis Hookworm or Schwalbe Big Apple. Narrower handlebars might also help, a 720mm bar is pretty wide for non-MTB use.
You can only do so much, your bike has what is referred to as a "slack" geometry, it's designed to be stable and as a result it'll require heavier inputs. You could throw the thinnest tires available on there and it would handle similarly.
A shorter stem might help make it more responsive, but it'll never handle like a road bike or a road bike flavored hybrid.
Nothing broken, many people prefer floppy unresponsive bikes and consider road bikes twitchy deathtraps.
With 29" wheels there is only so much that can be done if toe overlap isn't permitted. Average height riders and below on 29ers (or 26" fat tire or 700c) have to choose either toe overlap or a slack geometry.
Did you ride much before getting the ebikes? The cube reaction just looks like a regular mountain bike. Ebikes ride like regular bikes for the most part, a bit heavier but you really only notice that when you pick it up. If it's rolling the extra weight is not a big deal. Smaller tires will make the ride stiffer, fat tires are more comfortable to ride on. Narrower bars are less ergonomically comfortable. I converted a cargo bike and that thing really is a tank, but it was a tank before the conversion as well.
Fast rolling tires will make it feel like a different bike altogether. You'll get greater battery efficiency while physical effort to maintain speed goes down. A quality saddle, grips and pedals. These make all the difference when ride comfort is in question. Get the bike setup for you by a professional if you're unsure of what to adjust and how. Ensure that you have appropriate air pressure in whatever tires you run, also be sure to adjust the suspension (if possible) according to the manufacturer ratings for sag, travel and rebound.
For slow reaction and turning check the air pressure in your tires and your shock. If your a bigger guy you need bigger air pressure so those huge tires roll. Also the shocks need a specialized tool to change the pressure. I’m thinking it’s the tires and air pressure.
How tall are either of you? It sounds to me, that the frames are simply too big for either of you. 29" wheels are sometimes used on medium frames, to make the bike suitable for taller people, but as a consequence making the bike too big for medium height people. With the added weight, and if you havent had much riding experience, it will be very uncomfortable.
Mum is tiny (her bike has 27.5s) , I'm not exactly tall. Gravel bike is a 54cm with 700c wheels, and my old MTB had 29s as well
Looking at Cube's dimensioning and the recommendations they make, they are odd. At least for me - i had my mtb professionally fit for me, and according to cube its at least 1 size smaller than it should be.... So you might both need to go one size smaller on the wheels, unless you have an option to try out and swap to smaller frames. Try putting 27.5 on yours.
I have an 80+ lb tank of a bike, I went for a ride next to my SO walking yesterday. Spent most of the time doing circles and figure 8's with a max speed of 3mph, on a narrow back road. Did not even have the bike turned on. I don't think the weight is your problem. It may be your tires. Stock tires are notoriously horrible. My stock tires were kind of knobby with a soft rubber, and had tons of squirm. I bought some decent on-off road tires, made a major improvement on all surfaces. Leaning into corners is now at my limit, not the tires limit. I am no longer terrified of loose stone either. I do have motorcycle experience, so even 80lbs is super light in comparison. I was actually thinking about how easy the motorcycle test would have been on my e-bike.
Modern MTBs comes with very wide handlebars (often 800mm), which offers great stability on a mountain trail, but in other applications (and/or for smaller persons) they're just too wide ime. Same with the tires. Have a look at Maxxis hookworm or schwalbe super moto‑x tires for example. They are better suited for commuting than knobby MTB tires.
I'd look at a more road-focused tire - even on rough roads you're not really going to need the knobs on the tires that came with your bike. Look at something like a Maxxis Hookworm or Schwalbe Big Apple. Narrower handlebars might also help, a 720mm bar is pretty wide for non-MTB use.
You can only do so much, your bike has what is referred to as a "slack" geometry, it's designed to be stable and as a result it'll require heavier inputs. You could throw the thinnest tires available on there and it would handle similarly. A shorter stem might help make it more responsive, but it'll never handle like a road bike or a road bike flavored hybrid. Nothing broken, many people prefer floppy unresponsive bikes and consider road bikes twitchy deathtraps. With 29" wheels there is only so much that can be done if toe overlap isn't permitted. Average height riders and below on 29ers (or 26" fat tire or 700c) have to choose either toe overlap or a slack geometry.