I am sorry I did not fully follow the discussions earlier.
I only recall it was supposed to exist some compatibility
layer at some point.
But I keep all the time needing to
$ sudo rm -f /var/lib/rpm/__db*
there is no need to do so
because I forget and use yum instead of dnf in rawhide.
I am not really needing anything special, just install
a package, or run "dnf update" to update rawhide
but why do you think you need to touch anything below
/var/lib/rpm/? that's the rpm database you should never
touch without damned good reasons like follow dist-upgrade
instructions
you can happily use "yum" and "dnf" on the same setup
all the time and the warnings "rpm database modified"
or similar are harmless, you may even trigger them by
touch the rpmdb by hand