This could make real sense for ssh host keys, since they need to be used without presence and they're generally tied to the lifetime of the machine anyway.

I saw a write up where someone successfully got sshd to use a host key from a fido2 yubikey without touch, but I can't find it...

As far as "TPM vs HSM", it is soooo much simpler to make a key pair with a fido2 hardware key:

  ssh-keygen -t ed25519-sk -O resident -O verify-required -C "your_email@example.com"

You can get them for <$30.