You're not blind, and your fingerprint is right. I pulled packer-plugin-xenserver_v0.11.4_SHA256SUMS.sig off the GitHub release and ran gpg --list-packets on it, and it reports issuer fpr v4 0DD2E92A7A0F682BC29F87073084D82948625D89, which is exactly what you pasted.
It doesn't match the XCP-ng key because it isn't ours.
The plugin our docs point at is ddelnano/packer-plugin-xenserver, maintained outside Vates, so it's signed with the maintainer's key while 34AC2EB6... only signs XCP-ng RPMs.
I couldn't find that key published anywhere either. It's not on keys.openpgp.org or keyserver.ubuntu.com, it isn't in the repo, and it isn't among the 11 keys at github.com/ddelnano.gpg.
That looks like something worth raising on the plugin's own issue tracker, and you'd file it better than I would since you're the one trying to verify a download. I'd also say our IaC docs could stand to mention the plugin isn't ours, which is what sent you looking at the wrong key in the first place.
