if you are serious about staying longerterm, I would recommend asking an agent what your viable options are.
As already confirmed, you can extend your current 30 day exemption for another 30 days at immigration for 1900baht, I think as early as a week before your current stamp expires and you will get 30 days beyond the stamp date regardless.
Border bounce is an option, but they don’t like to see too many of those, it raises suspicion you are trying to game the system.
You can apply for a sixty day tourist visa in Singapore or Hong Kong etc too
I live here and I am married to a Thai. I got married when I was here on a visa exemption. If you are over 50 I would recommend getting the Retirement visa rather than the Marriage, aside from the higher bank balance requirement, everything is much much simpler for the Retirement visa.
Getting a bank account is a spin of the wheel of luck. I gave up and used an “agent”, cost me 1000baht.
Your biggest hurdle is getting the permission to marry certificate. That is going to be your main priority.