Visa’s are new every year. You’ll have to reapply and provide required evidence. There’s no limit of times, can be 30 years but probably a limit of one wife at a time for visa qualification. 🙂
Might want to look at language schools as well. Yes you would need to do the Non O marriage to a Thai and you have the option to add a WP or a Non B which can affect your stay in Thailand as you lose the visa extension if you quit/get let go but the same would happen on a marriage visa if you quit or were let go by the wife.
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.