Thanks very much for the patch!

I installed this patch by first installing tramp 2.8.0.1 in Emacs 30.1 from ELPA, then applying the patch, then starting Emacs and recompiling tramp.sh and tramp-sh.el, then restarting Emacs.

This did not quite have the expected effect.

The error from vertico was gone, but when I type a single slash at the find-file prompt, I now get prompted to log in to an SSH host. This sounds as though two lists have gotten out of sync: one with the empty entry, and one without. Do let me know if I can do further investigation.