Have no idea what's she is on about.
Just add this suggestion to your options.
Fly out with your US pp and enter Vietnam with UK pp.
Think that's possible.
Others will confirm.
UK pp visa exempt entry to Vietnam.
Saigon ripper joint for mini holiday.
Return to Thailand visa exempt (it's not VOA)
That stamps you in for 30 days.
Over 50?
Obtain a non O based on retirement.
You have a Thai bank account so have 800k in your account on day you apply for non O