sorry to say, but the Thai embassy and the consulates in the USA discontinued handing out multi entry Non-Imm-O retirement visa. Only single entry can be had, and the 1-year multi entry Non-Imm-O/A visa
just wait until your next extension is due. It seems they want proof of your income source, so they can tax any earnings you transfer to Thailand, by next year. since many countries have a "double taxation agreement" with Thailand, the source is important for the Thai tax authority. So they will not just accept a WISE transfer but actually need to know the source . . . it seems to be the road to the OECD "world income" taxation
I got the DEEP suspicion that this is just the beginning. Thai government plans to put a tax on foreign earnings coming into Thailand. So this would explain why they are beginning to collect proof of pension income from now on, which they can pass over to the tax authority by next year
"I know someone who" and how many years back was that? You cannot enter unlimited with visa exempts any more. You will be denied entry after the third time
that's not how to proceed. If you got two citizenships, you enter and leave Thailand with the Thai passport, book the flights and check in to the flights with the UK passport. It's the common practise since years