In regards to a suggestion to use sessions: no, not for me, never used them.
Before the catalog came up, I was using the regular folder tree that showed on the side - just like it does in Adobe Bridge.
To Phase One:
You need to do an announcement that you are sorry for the trouble your unstable catalog has caused many, many users.
Then you need to announce the date when Capture One Pro 7.5 will be out with a widely rewritten code for the catalog (tossing out that old code that Phase One took from Microsoft Expressions, written for much older computers). And, as you are at it, getting keywording to the great level it's been done in the Lightroom catalog since version 1.
And this must not be a paid upgrade.
On the other hand, many say that Phase One is an arrogant company with a condescending attitude towards its customers.
If those people are right, we will never see a 7.5.