I'm surprised after 2 years in Thailand, this is the first time you encountered a wacky foreigner. Now that the Covid restrictions are lifted, you will see a lot more.
My point is, you are more likely to be pulled aside if you have an expired "banned" or "overstay" stamp versus a clean passport. Note, I did state obtain a Visa before leaving her home country. Thus, not suggesting she try to sneak in. Just offering a suggestion to avoid extra scrutiny.
After waiting for the 5 year ban to expire. Just saying, it would be better to have a clean passport, versus a stamped one. They usually flipped through my passport looking at the stamps.
They usually flip through my passport looking at the stamps. One questioned me about the "Aruba" stamps. "What is Aruba?" "Where is Aruba?" Had to restrain myself from singing the old Beach Boys song.
Apply for eVisa on-line, before leaving USA. This will get you 60 days, instead of 30 days Visa Exempt. Can get at least one extension in Thailand for 30 days. So 90 days EZ. More than that, you will need a nother Visa like the retirement Visa. Or fly out of Thailand (Cambodia, Vietnam...) and fly back.