What long-term visa options are available for Polish citizens to stay in Thailand?

Doubt it, sorry. Just wait.

Mate ... to keep it simple ... you won't be going any time soon

The only right answer u can find at your local Thai embassy , they have the latest requirements and they can give u direct answer on the question

There are possibilities, but all of them are rather complicated and quite expensive. You could sign up for a degree program at a university for an eligible ED visa. You could take on a job offer (and get pre-approval from the Thai ministry of labor) for an eligible Business visa. You could arrange for a medical procedures for an eligible visa for medical purposes. Unfortunately, at 41 years young, that kind of sums it up already. The STV is currently available only in a hand full of "safe" countries. Which des not make sense at all, as everybody would have to go through the exact same safety procedures (tests and quarantine) as everybody else. The other visa categories don't have this requirement. So currently, old people 50+ (on an O-A or O-X visa) can get in for a longer time visit, while younger, more healthy people cannot on a STV. We can only hope some people of the less educated sort in charge of those kind of decisions wake up anytime soon.

I wouldn't recommend you to come to Thailand nows because there's a unrest political crisis. It could have a battle between pro-democracy mob and police or army could shoot people same as Nigeria