It depends which agent at which immigration office, there's no conformity here. I did it this year with my wife as well, in other words she is included with our translated and certified marriage certificate.
If you do it through an agent it's not a problem, to do it by yourself? I have no idea, I did it and apart from having to sign at least 25 bits of paper there was no problem.
I can't guarantee this now because it was a number of years ago when I did this but my wife and I flew to KL and back the same day to extend our visa by an additional 30 days before we left, nothing was said when we returned to Don Mung, we live here permanently now, it was probably about 8 years ago.
I live permanently in Thailand now, but only a few years ago pre covid I flew Air Asia from Hua Hin direct to KL and returned back the same day on the same plane, no problems, but the flight has never been available since Covid.
Cheaper and much quicker to get on a rubber boat at Calais, it's free travel, free hotel, free food and you don't need any health insurance once you arrive that's free as well.
It depends how much aircon you use and wether you pay government rates or Condo management rates, 5000 baht would be the Condo Management, government rate more like 1500 to 2000 baht.
Bangkok Bank is the only international Bank and seems to be preferred by Immigration, at least where I live but might be different elsewhere, nothing is consistent here, it costs to use an agent but very convenient if you don't want to tie up the