@Stuart ********
, thx a lot for your answer and everyone else for their input.
I have absolutely no problems with the financial requirements, having the 800k in a Thai bank account already for several months now and even the 65k as a steady monthly income.
My only concern was whether or not one could apply for a Non-O visa within the country, as we can't hop across the border and come back "exempt" anymore (and for a long time ahead, I guess), in case anybody else had experienced this situation.
Checking directly with the immigration office now seemed to me quite irrelevant as we all know everything in this matter changes faster than the weather these days.
I guess I'll go and check with them around February and see what their suggestions are then.
Maybe I'll have to first apply for a 60 day covid extension, as you suggested, before applying for the Non-O itself later on.
Thanks again everyone,
Cheers