Yes, you can study Thai as a second language or Muay Thai if you’re into fitness on an Ed Visa. Do not think you can enrol and not turn up, you MUST attend the classes scheduled or immigration will revoke the visa.
A work around would be to get a Non O (3 months) and open a bank account and then apply for an Ed-Visa (12 months). This will give you 15 months to transfer 65k baht pm into your account. Once your Ed visa expires, you can apply for a visa based on retirement and use that 15 months proof of funds, for your application.
I’m interested to hear from you what other countries are both more beautiful and easier to retire. Genuine question because I would be willing to explore