I rely on Bitwarden (slooowly migrating from… a spreadsheet…) and am thinking of keeping a master backup to be SyncThing-synchronized across all my devices, but I’m not sure of how to secure the SyncThing-synchronized files’ local access if any one of my Windows or Android units got stolen and somehow cracked into or something. I’m curious about how others handle theirs. Thanks in advance for sharing!
keepassxc database synced with syncthing across devices
This is the way OP. Centralised services are just too much a target for bad actors.
You already have syncthing so most of the way there.
Also built in TOTP / 2fa is pretty great.