Are you installing Workstation (which uses the new-style browser-based installer) or one of the other editions/spins (which use old Anaconda?)
For old Anaconda, this is discussed here. “Goal A” is the one relevant for you - you want to wipe and reuse just one subvolume. There are a couple of suggested ways to achieve it there.
However this doesn’t apply to the new Workstation installer - I’m not sure how you do it there. One option would be to avoid the new installer by using the “Everything ISO” (aka netinstall) to install Workstation - that way you’re using old Anaconda.