Bitstamp is my number 1, UK banks seem to approve of this the most…
CoinJar, CEX.IO, and OKX are also top tier, i personally use all 4 and split big wins equally across the lot. less likely to come under scrutiny from the exchanges. and if one does mess you around you’ve only a quarter of your pot locked up in hold.
I’ve always kept my withdrawals below 8,000 USDT, no reason other than I think its low enough to not trigger anything. I once had 8 withdrawals sent to my kraken pro wallet , 8,000, 7,999, 7998 etc… in about 15 minutes and never got any blocks. I could have just been lucky though.