[KennyBlanken]

Keepass + your choice of file sync. Keepass's database has file-based locking so it's safe to sync just via filesystem.

I like KeepassXC one Android and MacOS; Keepassium free-tier on iOS works great. On Android you can use syncthing, but syncthing doesn't work on iOS, so I use NextCloud to sync everything now.

[Firehawke]

Keepass2Android supports Dropbox, Onedrive, and a few other ways of direct sync. https://play.google.com/store/apps/details?id=keepass2androi...

For Windows 10/11 users who use a MS account, put a portable copy of Keepass on OneDrive and it'll be there right after a fresh reinstall plus sign-in, and you can access it from the Android app using OneDrive sync built into K2A.

[kenniskrag]

Keepass2Android also supports webdav, http, ftp, sftp and nextcloud directly

[anmipo]

For Syncthing on iOS there is Möbius Sync. However, it struggles with background updates (due to iOS restrictions).

[emaro]

For iOS I can also recommend Strongbox.

[orhmeh09]

Safe even on NFS? ;)