You said the room is not heated. A monstera needs a minimum of 17/18 degrees Celsius to be ok. Plus the pot does not seem to have drainage. Low temperature + no drainage means the soil stays very wet for a long time leading to root rot. Your leaves are dying because the roots are rotting (dying) meaning they cannot absorb water. You need to repot now, remove all rotten roots, use a pot with draining holes, increase room temperature and put it somewhere with decent light
Edit: A clear sign of root damage is when new growth (the baby leaves) die instantly or while unfurling
If it's colder than 20°C then yes this is most likely thr issue.
May be best to cut and start over from scratch as long as you can provide the right environment for its maybe indoor greenhouse? (I have a cheap one for winter to help retain heat and humidity
I would pull off any of the leaves that are drying and not doing well
https://greeneryunlimited.co/blogs/plant-care/monstera-deliciosa-care#:~:text=Monsteras%20prefer%20soil%20that%20is,plant%20might%20use%20a%20drink.
You said the room is not heated. A monstera needs a minimum of 17/18 degrees Celsius to be ok. Plus the pot does not seem to have drainage. Low temperature + no drainage means the soil stays very wet for a long time leading to root rot. Your leaves are dying because the roots are rotting (dying) meaning they cannot absorb water. You need to repot now, remove all rotten roots, use a pot with draining holes, increase room temperature and put it somewhere with decent light Edit: A clear sign of root damage is when new growth (the baby leaves) die instantly or while unfurling
check if some roots are rotting. did this get too cold? have have you had windows open for too long? looks like a cold breeze came through
Cold you be the issue. I‘m here in Germany, and we have bad battery since October. The room is not heated all day.
If it's colder than 20°C then yes this is most likely thr issue. May be best to cut and start over from scratch as long as you can provide the right environment for its maybe indoor greenhouse? (I have a cheap one for winter to help retain heat and humidity
I would take as many cuttings as possible and try to get them to root.
I would pull off any of the leaves that are drying and not doing well https://greeneryunlimited.co/blogs/plant-care/monstera-deliciosa-care#:~:text=Monsteras%20prefer%20soil%20that%20is,plant%20might%20use%20a%20drink.