a non-o has no medical or criminal background check or insurance requirement. It can be extended for one year every year. The OA (i think) can be extended by 1yr one time, then you're done and it can't be done again inside Thailand.
They will see your latest tm30 as soon as they bring you up on the computer. I've never brought a tm30 receipt to anything for immigration in hua hin. I just being copy of my lease
SWIFT is flat rate so (unlike Wise) larger amounts are lower cost. My monthly transfer used to average about $26 in fees from wise (small amounts like ฿70-฿100k). Large amounts like ฿800k would be excessive. It costs me flat rate of $15 to send via SWIFT regardless of amount. Always send in USD and I usually get near mid-market rate from Thai bank.