At the end of the day, you were granted entry as per normal. Questioning with an extensive history isn’t unusual, they are just doing their jobs. And as always - it was referred at least one level up. If you can prove yourself a genuine tourist, great. Just carry on.
lol, you don't have to spend a penny of it. The visa cost is only 50k baht for 10 years multi-entry. It's the cheapest visa out there. If you can get LTR, no point chasing after residency
It's an absolute no-brainer if you qualify for LTR. 10 years for only 50 k, tax free status, and very easy application process. Prove you have the income, get the visa. If you have a complex income situation, an agent MAY be able to help sort thru it so the BOI can process easily. But consult with BOI first. Thai Privilege is the poor man's version. If you don't qualify for LTR, TP is an excellent visa. Just pay your money and come on in. No need for agent at all.