I've cancelled my subscription yesterday, conveniently it was about to renew at the end of the week, so I have a few days to migrate from Proton, here's what I'm thinking of, but I'd love to hear what other people are switching to
KeepassXC and Strongbox on iOS. using mailbox.org webdav (via rclone mount for KeepassXC) for my vault sync, plus yubikey slot 2 HMAC challenge response which works great. Not missing vaultwarden too much