FTX has always been a bit of a joke in the crypto community. I elaborated in a previous comment.

Kraken has been a bastion of sanity amidst the chaos for a decade now. No prop trading, no dizzying corporate structure, no "liquidity" issues, no stadium sponsorships. They're just chugging along in the background, keeping their site online, publishing regular audits, and running the business like adults. I intend on holding BTC indefinitely, but if anything happened to Kraken it would likely change my mind.