Catalina App Store not responding with the new user (NEW) I want to keep

Hello,

I wonder if you have some idea on how to have App Store work with the new user given below situation?

[Symptoms]

when trying to open App Store (version 3.0) on my MacBook Pro (Retina, 13-inch, Mid 2014), macOS Catalina (10.15.7), it does not respond (I see the window but not the contents) almost forever and I have to manually force quit.

[Background]

• The MacBook Pro has gone through several OS upgrades (10.10 -> 10.12 -> 10.14 -> 10.15).
• I have two users on my MacBook Pro, one is the old user (hereafter OLD) which I was using from the beginning, the other is the new user (hereafter NEW) which I had to create during 10.12 -> 10.14 upgrade and I am currently actively using instead of OLD.

[Attempts]

as per https://discussions.apple.com/thread/250717258 I tried

• safe boot: did not solve the issue
• log in with different user: the issue happens with NEW, but does not with OLD