unless you have an Elite visa or the LTR for wealthy individuals most other long term visas are 1 year at a time. As others have recommended it’s better to get acclimated and rent for a while (maybe forever). Not always but often when you have a property it’s difficult to sell.
It’s amazing how much easier and less worrisome life can be if you want to stay long term by getting an appropriate long term visa. Trying to get around the system will eventually put you in a precarious situation.
I’ll go out on a limb here and guess that 99% of those working in Thailand remotely, online in other ways such as teaching Chinese students, making a living as digital creators etc are working off the books and in most cases illegally as far as visas and work permits go.
No, you can’t work on the wrong visas including retirement visas.