I have the pensioner LTR. I doubt you will be approved if you can’t submit 1-2 years of tax returns showing passive income. There is no cost to trying but I don’t think it will happen. I applied for my pensioner LTR in 2022 while I was in Thailand on an OA visa. It was easy to apply online from inside Thailand. When you go to get your LTR stamp in your passport they will move you from your existing visa to the LTR.