I've been coming and going in and out of Thailand for over 20 years on a regular work rotation and never been asked to show cash however if it worries you just bring $ and relax.
800k in the bank for 3 month prior to visa application. The actual fee is very small 1900baht I think. Then also re entry stamp if you intend to leave Thailand at any time, multiple entry is best.
Takes about 2 weeks now as things have all changed recently.