so the second volume should be only for catalina?
You can put whatever on Earth you want on there, mate. All I want you to do is make a fresh install of the OS. Whether you wipe the current volume and do it on there or on a new volume, doesn't matter. Whether you put a billion new files on the volume also doesn't matter. As long as you install the OS anew, you'll most likely be rid of this issue and any other issues that may be caused by the same underlying problem