release the binaries in arm64
make the UI adaptive, you already have a phone design in you're webapp but this would be native linux support which will allow notifications.

I'm a developer and If this was an opensource project I'd volunteer to do it for you but its not, still if this is being discussed feel free to contact me if I can help.

otherwise, when I get the time as I'm currently working on xdg-desktop-portals-lomiri and other things I'll use the unofficial API to create a client which I'd rather not.