Given the above recent arguments, I don't see why so many think this will not affect them. Seems pretty obvious to me. If you stay here longer than 180 days, the Immigration office will require to see your Thai tax return before they renew your O-whatever-extension visa. Showing them some Thai-US, UK or Aus tax return and waving the Double Taxation Treaty will mean nothing to them. This isn't new. Anyone on a B visa then a Thai work permit does this (or maybe their company does it).
As others have said, anyone - including pensioners - living here more than 180 days next year will need to fill out, file and receive back the Thai RD's 2024 tax assessment/return and tax receipt showing what you paid that year (or confirmation from the filing that you own nothing - presumably as you show the taxes paid in the Double Taxation Treaty country's tax return). Only then will you get a new visa. As the article mentioned, that could take a couple of years to work out getting all the foreign paperwork together. Visas might be renewed on a exceptional basis during that transition period.
If the new plan to tax all foreign income is confirmed to be based on global incomes, the bill will be high, if you've so far avoided paying tax on it in your home country (e.g. because you are a non-resident there) and the amount could therefore be high in Thailand. If it's based only on foreign remittances (each documented and maybe tax withheld by the Thai receiving bank), then maybe easier (to file) and cheaper and smoother for the visa renewal (retirement, marriage, etc). Meantime, fill your Thai boots/bank accounts with foreign remittances before 31 December and live off that ass long as you can.