Anyway, trying to install them results in conflicts with the x86_64 versions which are preinstalled (and obviously pretty important). Trying to install e.g. glibc.i686 results in
Error: Transaction check error:
file /usr/share/doc/glibc/INSTALL from install of glibc-2.29-15.fc30.i686 conflicts with file from package glibc-2.29-9.fc30.x86_64
file /usr/share/doc/glibc/NEWS from install of glibc-2.29-15.fc30.i686 conflicts with file from package glibc-2.29-9.fc30.x86_64
So how can I achieve having the 32-bit and 64-bit version of a package installed?
Is your system up to date? You should be able to install the 32bit package just fine. Here, the error is because the 32bit package is a different version than the 64 bit somehow (2.29-15 vs 2.29-9). That should not be the case. Try:
Thanks for that hint. I had tons of duplicate packages installed, e.g. glibc-2.29-15 and glibc-2.29-9, both as the x86_64 version.
So, I cleaned the old ones up using sudo dnf remove $(dnf repoquery --installed --latest-limit=-1 -q --exclude=kernel\*).
Afterwards, installing the 32-bit pacckages went just fine