Expats have a country they can go back to. They usually have a passport allowing them to travel. They had access to education and medical care. These people have no country, no identification, no rights, no future. Thailand did right.
If you ever had chickenpox, get it. The nerve pain is intense and unrelenting during the attack. It is also recurring. I'm living with neuropathy after the last bout. Get the vaccine if you can.
From the tax perspective and cost the LTR-P (Pensioner) is the best option if qualified. No tax on amounts remitted to Thailand from abroad. Multiple entry permits. Preferred lines at airport (allegedly). One time fee of 50,000 baht.