Have you tried syncthing? It works great with keepassxc.

Vaultwarden is pretty easy to self host.

Maybe you will find this article interesting: https://linuxreviews.org/Zram

I recommend FSArchiver, it can handle different size partitions

For me: uploading single file using their client ~25MB/s, downloading ~50MB/s (30-60MB/s). In newer versions of their linux client it’s possible to mount filen as network drive or to start webdav/s3 server.

Install Termux and run sshd -D -d -p <port>

You can mount remote with rclone and fine tune caching to your liking: https://rclone.org/commands/rclone_mount/#vfs-file-caching