rez-pip2 ruff will install a Rez package of Ruff that has no tools defined in the resulting package.py file, so that it is basically useless. Of course this can be added by hand, but that should not be necessary.
The rez-pip that is part of the Rez 3.2.1 distribution does not have this problem.
I think it might be becauserez-pip2 only works with wheels, and the ruff wheel does not advertise any entry points.