Can I apply for a tourist visa at an embassy in a nearby country to avoid reentry issues in Thailand?

Be sure to read this post...it applies to you and your recent history of staying in Thailand.

4/

A visa is not a silver bullet. You're not going to checkmate then into letting you in if they have a problem with your history. Meeting all the requirements is all you can do.

why would you do that? You have no more chance getting back into the country on a tourist visa than you do on the 90 day visa waiver entry you get as a Brazilian.

Believe me if they're gonna give you a hard time it will be because of the covid extensions and the long time you've been here without leaving NOT because you're trying to come in on a visa waiver entry. Have a booking OUT of thailand to your country about 80-85 days after you're scheduled to arrive on the 90 day stamp. That's about all you can do is show them you ARE intending to go back to your country when the entry stamp runs down. (even if its a fake booking and you cancel that flight after you get in)