What are the requirements for switching from a non-immigrant OA to a non-immigrant O visa in Thailand when applying for an extension of stay?

I have a question about going from the non-immigrant OA to the non-immigrant O visa and doing the process by yourself instead of through an agent?

Currently, I’m on the non-immigrant OA, but at the end of my first year if I want to switch to the non-immigrant O, I have learned that it’s best to briefly go to a neighboring country and re-enter on the non-immigrant O 90 day to start the process cleanly.

My question is — since I will already have the banking history established in Thailand, what will immigration be looking for with regard to my residence when I apply for my first extension of stay? Will a TM 30 from an Airbnb be sufficient or will they insist on me showing long-term lease? Looking for first-hand knowledge, so please reply if you’ve actually done this yourself because it would be more helpful, since I’m not looking to go through an agent at this time? Many thanks.