^^^ Massively agree with the above & had similar shitty advice (from HR) in my early years working in Singapore that pole-axed my Singapore PR . End of the day you probably have a choice of going back to work for a few years or accepting living in Thailand as a "Guest", given your history i'n sure you'll always be a welcome "Guest" Good luck with whatever you do, please do let us know how you get on :)
I really think you've been badly advised. You could have long since had PR, and all this extension nonsense would be a thing of the past for you. They probably advised you to take the route that was easiest for them.
Sorry,I was answering the exam question... "Marriage or Retirement visa" for which given the information provided in the OP there is no doubt about what the correct answer is. If the question was actually "What visa should I have if I want to be a Thai PR/Citizen" then obviously, the answer is one that gives you a Work Permit (by definition not a retirement) for (at least) the next 3 years whilst you go through the process... To the OP... Simple question (trust me, recently retired for the 2nd time at 48 & get asked this at least weekly) ... Are you really retired or what?