with an METV you don’t need to do extensions if you don’t want to. At the end of each 60 day entry you can border bounce to get another 60 days. If it’s more convenient then once each entry you can buy one extension of 30 days.
Either way with one final extension you can milk almost 9 months off a METV.
That’s office dependent. In places like Phuket you need a filed TM30 every time you re-enter the country or even if you’ve stayed in a hotel or hospital in country.
Of course whether you need to file one is debatable. You really only need one for interaction with immigration.
It doesn’t take any time to “process” once you save the data inputted it’s on the system.
Why they said it was invalid is another matter. Perhaps they hadn’t filled in the data correctly. I see a lot of people where their passport has been entered wrongly or has the wrong country of origin etc. But it’s not because of any processing time.
That’s not going to happen. Before they all went online some embassies would only take the fee if everything was correct at application time.
Now they’re all on the evisa system there are no refunds. The onus is on you to ensure everything is 100% correct - even if there are glitches in the system. Sucks for sure. But that’s how it is.
Not too many options open for under 50. You’ve got the education visa for stuff like Muay Thai or Thai language that will work for a year perhaps two. Probably better to look at the DTV which is a 5 year visa. That would take you over the threshold of 50 where you could look at a retirement visa.