When a route is added to the club by copy, it is as though the "ownership" of the new club-route is not (fully) changed from the person that added it.

Only the person that added it can edit it (when I would expect any group admin to be able to).

Only that person can add Collaborators, and their personal id is not among the list to choose from, as though they are the owner.
I cannot see anywhere in the info on route, who this hidden "owner" is.

I suspect routes imported from classic have this hidden ownership as Chief Administrator's personal id.

When a route is added to a club by copy, and then the club-route version edited and save clicked:
The top left path changes from "|||\ Club Library" to "|||\ My library".
Clicking there then does take me to my personal library, not to club routes (as you would want).