If you happen to stop in phiksanulok between Chiang Mai and Bangkok I recommend doing it there. Did mine there last year... Super easy. I've been hearing Bangkok can be 4 hours or so but I don't have personal experience in Bangkok doing it
I'm the same... Now that I'm in the country in not following the entry updates anymore... People keep asking me about the Phuket sandbox and all I know is it's 7 days and need to fly direct into Phuket... Everything else in clueless as I don't care lol
cheers! I'm in my new hotel now but I contacted the government hotel and they said just to come Monday morning before 9. If I need another test at any point I'll come to you :)