Tailscale for your laptop, phone, etc. to be able to talk to the other computers when away from your home WiFi. (Optional, but makes syncing easier).

Syncthing, talking to your Tailscale IP addresses if you use it, or your private WiFi network addresses if you don't use Tailscale.

One folder synced, containing keyfile2.kdbx.

30 minutes to set up and then you almost never need to think about it again. If you don't trust Tailscale, you can run a Headscale server or just not use it. And the syncing is entirely run on your machines; your data never ends up written to someone else's SSD.

It's really not much effort.

I mean does it? I have set it up before but I just set it up for my new small office team. I already had an internal server and WireGuard vpn in our office and it took 2 minutes to create a quadlet to run vaultwarden and a few more to configure it. The “hardest” part was training the team on how to use collections.