What visa options should my partner and I consider for a long stay in Thailand?

Take a SETV for 90 days

@Lanny **************

METV is best for long-term plans ("as long as we can"), which you can only get in your home country. Even if you think you might not need all the re-entries of the METV, getting a SETV from an embassy in a neighbouring country, like you are thinking about, is a hassle, and will probably end up costing you more in the long run in travel costs. And getting multiple SETV's is more and more difficult, the more SETV's you have in your passport.

If you can meet the financial requirements the 6 month METV <- multi-entry tourist visa is a good option. It's good for unlimited entries during it's 6 month validity, and each entry gets you 60 days. When that 60 days runs out you can go to the border stamp out of thailand, stamp in&out of another country and then right back into thailand to get a new 60 day stamp. IF you use that visa correctly you can get almost 9 months of stay out of it.

Remember on Oct 1st 2022 until Mar 31st 2023 the 30 day visa exempt entry goes to 45 days and you can still get the one 30 day extension on it at the immigration office.

Keep in mind if you're thinking about border bouncing via land to get a new visa exempt entry you can only do that TWO times in a year.

You can also go to the thai consulates in nearby countries and get a single entry tourist visa which would give you 60 days and which you could extend for 30 more days once you're here.

So I will leave it to you to decide which is the best path, those are pretty much your options