Will I face questioning at immigration if I return to Thailand on a visa exemption after previous scrutiny?

The new entry and regulated amount of entries was implemented in November 25, so why they looked at previous entries… you only made one entry in December and after the tightened rules of entries in one year. Odd…

As other said and your self plan on getting retirement visa so apply for the first non-o (3 months and then you can do the retirement non-o for one year.

You can ask Thai embassy

In your home country how you should do to prevent a problem at immigration if you plan visit without the visa and go on exemption rule one more time.

But since you have visited several times during 25 then I understand why they say your should consider a proper visa.

follow the advice you were given, obtain a visa

Apply for your visa ahead of time on the Thai government website so you will know before you go.

I had same a few years ago. Just started getting a tourist visa every 3third visit. Las comment I had was last summer when leaving- why did you get a tourist visa 🤯

You been flagged already mate

Personally, I would have considered a safe entry service rather than a regular tourist visa in a situation like this. You have already been assessed as being at the upper end of what is typically accepted for ordinary tourist entries, and a tourist visa only provides slightly greater predictability than visa exempt entry.

Get a tourist visa for this trip

Taken away and questioned. Maybe you run a risk if they put info onto the computer system, arrive they may read and reject your entry.

Depends if they entered anything against your passport.

It really all depends on immigration officer you're standing in front of. I would definitely have a tourist visa and the three proofs, accommodation booking, 20,000 baht or equivalent in cash, and a flight out within that 3 weeks.