I created my own similar tool: https://filepush.kevincox.ca/
It is optimized for the case where you commonly send files to the same devices. For example I have set up all of my devices as well as my partner's phone and Steam Deck. Then I can just tap them and send the file with end-to-end encryption.
It is sort of cool that there is no backing server, just static files. All of the signalling goes over WebPush.