I use PGP for git commit signing, using GnuPG and subkey on a Yubikey.
I tried to test your AppImage distribution, but that failed to start on RHEL-10 due to dependency issues. Not had time to explore building from source.
My RHEL-10 setup might not be optimal (upgraded via an unsupported path from RHEL-10 Beta), so there might be some issues related to that too. Ny main gripe now with GnuPG is the complete lack of password caching for Yubikey operations requiring the private key.
I've tried oct too, same issue there.
That said, I prefer the Sequoia-PGP cli over gpg; Sequoia is the sanest to option use between the two of them.