Not self-hosted (not online at all, actually) and the apps are in early stages (read-only afaik), but I’d recommend Buckets. I’ve done the same search as you, and nothing has even come close to it. The license is a tad expensive, but it’s from the WinRAR school of licensing where it doesn’t disable anything. It just nags you until you buy it. It syncs with SimpleFIN and everything is in a single file, so I just have it in a Syncthing folder to keep it updated between everywhere (though it does have a built in sync function).