Homepage of the embassy in Paris is the one you need to read.
That said…
Get a NonO visa (OA needs a health insurance which you will probably replace later) or at least a tourist visa.
Open an account and put 800k in it (must be transferred so that it says foreign in a statement later!) and never touch it again.
Or
Assert that you will be able to transfer
*****
every single month to that thai bank account even if the euro looses 50% of its value.
I’m doing the 800k because I missed the 65k one month on my first try and had to restart (going back out of the country).
About 2 weeks before end of your visa go to the immigration and get your retirement extension. They will need a statement and certification from your bank and other papers.
There are other ways but those are the simple and sure paths to follow.
The immigration of your province will answer all questions (this is Thailand and nothing is written in stone)
If that is approved, you’re good, because the retirement extension (or LTR or whatever you want to get) are done within the country. Nobody will ever know about what happened before.
Your edit so clearly states “ this guy is using visa exemptions instead of regular visa to stay almost all year. He must be evading government for some reason”