It is backed up alongwith everything else, all my data, under a normal 3-2-1 idea, but 5-3-1.

Each of the copies on separate media inc my main PC is also versioned. I keep 12 hourly versions, 7 daily versions, 4 weekly versions, 12 monthly versions, and then per-year versions going way back. This helps protect against corruption, like I accidentally deleted an keepassxc entry without noticing right away or w/e.

I am shocked how many ppl think synchronization like syncthing act as a backup.

No synchronisation is not a backup. If you accidentally delete the database and it syncs across all devices then the database is gone. If something is broken and overrides multiple times then the history if it is enabled is also gone.

Pls use proper backup methods to backup your database.

Edit: I sync my database also with syncthing across devices. But to back it up i have on multiple clients system backups running that include the database.

I save a copy on my PC regularly (because I use keepassdx primarily, an android-only client), and I upload it to signal. Yes, I use signal as cloud storage, and it works really well! I have peace of mind that the file is encrypted using top-notch encryption, and only accessible by my linked devices.