What are some well-paid jobs in Poland outside of engineering/finance/banking/IT?
Basically none. And only some healthcare workers make good money mostly owners and partners of busy private practices.
Why don't you try opening up your own business?
Also, selling cars can be profitable but unless you can price a cars value just by looking at it and knowing how much it costs to fix different things on various cars you'll lose a lot of money. I flip a few cars every year mainly to have a different car every few months and make some extra cash, but my first few trades were definitely losses. I wouldn't take a job at a dealership though especially not in Poland and not now.
This isn't Germanistan or the United Kaliphate where you can sit on your ass all the time and the government will provide for your every need. In Poland you have to work to survive, no one's just going to give it to you.