I know that if you are on Visa exempt entry or Tourist visa, you can extend 30 more days for 1.9k baht, even if you were on overstay. I did it a few time myself. If it doesn't apply to Covid extension, well, you are looking at a 23k baht penalty upon leaving on April 19.
I've extended my visa 30 more days while on overstay before but it was never the Covid extension. You know people who got denied the extension due to overstay?
Thailand Pass is NOT a visa... it's a extra layer of requirement due to Covid. You came into Thailand without a visa so because you are from the USA you get the 30 days visa exempt entry stamp.
It's very easy to transfer money from Thailand to UK, I do it every month with Ripple Technology from SCB Easy and the transfer speed take 30 seconds. The rate fee is very low:
If you leave on the 19th, your fine will be 23k baht total given that it's already 12k. If you can't pay the fine you will be jailed. You had the chance to extend your stay with the Covid extension Friday March 29, or earlier this week with overstay penalty, but didn't do it. Nothing will happen to you if you extend while on overstay, you will simply pay the overstay fine and get stamped 30 more days from the day that your visa ended. So if you go today your extension will end around April 26 and you will pay today 12k+1.9k+1.9k, so 15.8k baht total.
I'm not talking about fast-track entry, I'm talking about arriving at Suvarnabhumi Airport, and while getting interrogated you call Thai Visa Advice, they can help you on the spot, no need for pre-arrangement or wtv. It's more costly than having pre-arrangement with them, but that pre-arrangement means that you pay no matter what vs gambling that you can get in and paying more if they want to denied you.