Hopefully that's a false dichotomy and the entire Free Software community doesn't end up reliant on Microsoft to host all our keys for us. The article goes on to mention key transparency, though, which does seem like the right solution.
I note that rekor (the transparency log implementation used by sigstore) already supports signing with SSH keys[0], so this TechRepublic article about it[1] from March (which lists only "GPG, x509 and Minisign") is already out of date.
[0] https://github.com/sigstore/rekor/blob/main/types.md#ssh
[1] https://www.techrepublic.com/article/a-new-linux-foundation-...