Good catch, I didn’t realize that with AnyType. That makes my first recommendation to OP just SilverBullet, then. Source available is better than nothing, like with Obsidian, but OP specifically asked for FOSS repos. It looks like their peer to peer sync server is MIT licensed, but their client (and client library) code is licensed under the “Any Source Available License 1.0,” which restricts use other than for “personal, academic, scientific, or research and development use, or evaluating the Software, but does not include uses where the Software facilitates any transaction of economic value.”
I ruled out Logseq’s sync service due to it being both paid ($60/year minimum) and not FOSS, both things OP asked for. For my purposes, since it’s not FOSS and not able to be self hosted, it’s not a good option. But it makes sense to use the same file syncing solution that’s already in use, whether that’s FolderSync (or some equivalent tool) set up to sync to my server, Syncthing (though I just realized its Android client is no longer being developed as of December 2024), or even Cryptomator + some cloud storage service.
You can use a controller. I got further in Dead Cells on my phone with the Backbone One than I did on my Steam Deck. Maybe the same would be true with Hades - it’s a shame the Netflix version doesn’t (or didn’t; I haven’t checked in months) support cross-save.