What are the best long-term visa options for studying Muay Thai in Thailand for 3 years?

What’s the best visa option(s) to stay in Thailand long term (~3 years) to study Muay Thai? I’m from the USA.

I know an ED visa can get me one year. I’d be ok learning Thai. If I choose to take another year (or 2) of language would immigration be suspicious? I would actually go to class. I like languages but I want to focus on training.

I know some gyms sponsor ED visas but I may gym hop so I don’t know if I will commit to one place more than a few months.

Another option is 60 day tourist visa extendable to 90 days. I don’t mind a border run every 90 days if the visa can be reused a few times but I think a border run on the 30 day visa extended to 60 days is too frequent.

I’m not over 50, have no family there, and don’t work for a thai company so. The only other visa that’s available is the elite visa but I don’t have the funds. I’m ok doing a visa run a few times a year, or every 90 days spend a few days outside and apply for another visa but I also know they get suspicious if you border run too much. Also I want to focus on training so I don’t want to spend too much time running out, waiting, and applying for visas.

Thanks for any advice.