https://github.com/FiloSottile/passage :)

That's exactly the use case I set out to replace for myself. I'll put together a guide at some point. The part I don't use and so can't really own is the mobile app, I would love a community solution there.

I am also planning to integrate https://github.com/FiloSottile/yubikey-agent which makes the SSH authentication part very easy, so that you only type your PIN once and it stays cached.