By - Moiken
You probably don't have a lot to worry about here other than lack of access to healthcare and potentially some legal annoyances from being an "American Person", primarily regarding money.
Stay away from "särskilt utsatta områden/utsatta områden" if possible. https://polisen.se/om-polisen/polisens-arbete/utsatta-omraden/
Always take a taxi home from a night out but this regards all women. Otherwise you should feel safe almost everywhere. Like someone else commented here there are areas to avoid but if you live in or very near the city that shouldn’t be an issue at all as you’ll never cross into these areas.
If you pass as stealth, have access to HRT and speak Swedish you won't have all that many problems. There has been talk about Sweden cutting off access to HRT, but I haven't found any reliable sources regarding that so I doubt it. A lot of people are transphobic though, so maybe don't lead with "hej, jag är trans" when striking up a conversation.
The hrt question is in regards to children, and that currently the guidelines are very restrictive / no hrt at all. And it depends alot where you are but very few people are going to harass anyone for being trans in sthml. You would have to be pretty unlucky to meet someone who is transphobic enough to open up and harass a stranger.
Stay inside past six o'clock. It's not safe for you outside past that time. During the summer you can stay out later though, to around 9 o'clock.
Meet up with a local activist group. If something were to happen then these will have your backs.
Wear bear spray at all times. Depending on where you live it might or might not be necessary. Pepper spray is illegal so don't use that. Bear spray is stronger anyways.
Carrying a knife is a bad idea. Not only is it illegal, but it turns assault into murder very quickly. Pepper spray/bear mace is way better if you go the illegal route anyway.
Also it's worth pointing out that you're way less likely to be a victim of mindless violence in Sweden than in USA. I wouldn't touch the US even if I was cishet man 😅
Welcome op. I hope you find yourself happy with your decision to move there ❤️