Is it better to apply for a Non Immigrant OA Visa from abroad or to enter Thailand on a tourist visa and then apply for a Non-O Visa?

O visa is definitely better than OA as you have to buy mandatory health insurance.on renewal of OA. The health insurance could be increasingly costly with advancing age and does not offer protection for pre existing health problem, also most company do not accept applicants over 65

Okay, let's quickly re-cap this

IF you decide to get a Non-O-A (Long Stay) visa from the thai consulate in your country before you come here, you need a police background check, a medical certificate, proof of at least 800K baht or 65K baht a month in income in your country, AND you need BOTH the 100K USD covid insurance and the 40K/400K out/in-patient regular health insurance FOR A YEAR.

Now if you decide to get a 90 day single entry Non-O visa from the thai conuslate in your country before you come here, you need proof of funds AND as a rule BOTH the previous insurances for the 90 days you'll get stamped in for too <-(note at some consulates they just require the covid coverage for 90 days)

BUT

IF you come in on a visa exempt entry OR a 60 day tourist visa entry you only need the 100K USD covid insurance for the time you'll get stamped in for and then when apply for the 90 day Non-O visa INSIDE the country at the immigration office you do NOT need any insurance, you show proof that the 800K baht was transferred in from abroad and apply for the Non-O when you have 15 days or more left on your stamp.

It's the crazy prohibitive insurance coverage required that's the reason people are comin' here visa exempt or on a tourist visa and doing the Non-O and year extension inside the country

Benefit of coming in on visa exempt is only 30 days of Covid insurance needed upon entry.

I got one in August. It depends upon the wheter you can deal with the bank requiement or not. Other than that there are a few more things you have to do

I second James advice. Enter on a visa exempt, then apply for a Non-o inside Thailand. It’ll save you money on health insurance

If you already have the funds deposited in your Thai bank account... Then enter visa exempt and get the non o for retirement inside Thailand at local Thai immigration office followed by one year extension of stay as retiree.

Much easier to do that than getting the OA visa in your home country.

No problem getting a non-oa visa. What’s the concern?