Hello, I am a trans woman living in on of the bigger cities in Poland!
Generally, if you live in one of the big cities you should be fine (most of the time). I’m am yet to have any issues, however I do avoid wandering alone at night and sketchy streets in general.
Most of the time even people I know are not tolerant will not give me too much trouble, however this might be very subjective and might vary significantly.
Sentiment online also seems to be not the nicest, and seems to be shifting a bit against our eastern friends due to political frictions and certain country doing some meddling, so I don’t know what to say future-wise. It is what it is.

In terms of communication, I feel like most young people know english at least a little bit, and a lot will know it at communicative levels, however older people will most likely not know a word. It should not be a problem at all at restaurants, but might be in a grocery shop or when asking for directions at a bus stop. As a native polish speaker it might also be a bit difficult for me to say, as I don’t really try to talk with people in english here lol

As for vegan stuff, well, selections are not the best, but it keeps getting better. Restaurants will often have at least 1-2 vege options, but it’s not a given and I always check menu before going. Afaik Warsaw is a bit better for this, but I’d still advice to make sure you’ll have anything to eat before going :D
For groceries Lidl seems to have best selection of vege stuff out of the ‘common’ store chains, but that is still not very wide. Luckily you can get almost everything on allegro (think amazon, but polish), so that works quite nice for some harder to find stuff you might need for cooking (as long as it’s packaged ^^).

As for language, the oldest people that were taught english from the beginning of their education as a foreign language are about 35-40. People older than about 50 were taught russian instead, but because almost nobody speaks it anymore they don’t, some of them learned english later especially for professional reasons. In some places especially along western border and in Silesia the primary foreign language taught is actually german so some people are trilingual but don’t count on it, and these are also people who you could expect to speak good english

Strictly speaking you can even get citizenship without speaking polish (but it helps). You don’t need it for residence permit (but you need an address for that) and i see that paperwork for this is done in english. Residence gets you PESEL number and this allows you to make an account in government service (called Trusted Profile) (and also an app) that allows you to do bulk of paperwork through it

In larger cities there generally are vegan options and if you cook on your own even shops in smaller cities (like 50k-20k) are supplied properly. I’d say that places like Warsaw, Wrocław or Poznań are decently tolerant, there’s plenty of exchange students from any country in the world maybe except North Korea, and the worst (as in most far right support) are small towns and villages in the east. Public transit is usable to the point that i haven’t needed a car for 10 years, and there’s an app for that too. Like germans and unlike americans, poles don’t do small talk. Contactless is accepted almost everywhere, online banking is fully usable without an app, everything that you can get shipped you can get on allegro. new SIM cards need to be registered before they can be used (ID or passport for foreigners). internet is cheap, fiber is available even in small villages and nobody gives a fuck about piracy

I can’t decide if I’m happy or sad that nobody has made the obvious joke. :)