That is an implict conflict between the packages nevertheless, since it results in a conflict, if one package is installed already and you need to install the other package. Of course, you can avoid the conflict manually by removing either package from the installation, but having to do that is annoying.
Agreed, and I already replied to that.
Now regarding the original question, we already have per-libraries virtual provides, we could generate more to match Debian packaging guidelines:
Before:
$ rpm -qP varnish | grep lib libvarnishapi.so.2()(64bit) libvarnishapi.so.2(LIBVARNISHAPI_2.0)(64bit)
After:
$ rpm -qP varnish | grep lib libvarnishapi2 = 6.1.1-4.fc30 libvarnishapi2.x86_64 = 6.1.1-4.fc30 libvarnishapi.so.2()(64bit) libvarnishapi.so.2(LIBVARNISHAPI_2.0)(64bit)
So one could `dnf install` or BuildRequires libvarnishapi2:
https://packages.debian.org/buster/libvarnishapi2
Now my worry would be Debian-like compatibility at the expense of metadata bloat.
Dridi