This thread occurs over and over on the Internet, including the banks, telling you that this year, there are increased security regulations that prohibit opening bank accounts on tourist visas. There’s no such law. It seems that Thai banks are franchises like McDonald’s. Each branch is individually owned, with its own policies, Which may vary according to which teller or Manager you talk to. They want to sell the insurance because they get a commission, and there are agents that help you open accounts, apparently by sharing their fee with banking staff. They also like to have a residency certificate, which you can’t get in Bangkok on a tourist Visa or Visa free entry, but you can in some other provinces.research this and keep trying.
Also, if you buy a genuine, refundable ticket, be careful, because you may get your money back, but you may only be eligible for a credit with the same airline.
many believe they refuse to do the T3, because they’re afraid they will have to pay tax on their income. Not sure if this is really true, but this lore is widely passed around on these groups.
you can also come on a tourist visa or visa exemption, and convert that to a Non O visa by reason of retirement. It is for 90 days. As soon as they put the sticker in your passport they stamp it “used.” Then, if you meet the conditions, you can extend it for one year. I did this in 2018, extended it each year ever since.