People just don’t learn.

Reminds me a bit of the MNT Reform: https://shop.mntre.com/products/mnt-reform

Path of Exile?

Ok, that’s great!

My concern is has more to do with metadata, wich can be collected. If there’s a local alternative or a self-hosted one for something, I’m more inclined to use these than something that depends on a third party.

No, thanks:

It uses a WebRTC peer-to-peer connection. WebRTC needs a signaling server that is only used to establish a connection. The server is not involved in the file transfer.

If your devices are paired and behind a NAT, the PairDrop TURN Server is used to route your files and messages.