This might help you as Prefs and other customisations are stored in the Premiere Profile folder.
Don't make any manual changes at all to data in the Folder directly.
Details in article
https://helpx.adobe.com/uk/premiere-pro/using/reset-preferences.html
Before you try any of this make sure you save a good known copy of he Profile Folder which contains all Preferences and Customisations.
Save it under a specific folder you create youself as back up - so you can go back to that known good Profile Folder to restore settings if something gets messed up.
Premiere Pro can be a bit fussy if Preferences get corrupted
Its not exactly an elegant solution as you have to manage folders manually, copy and paste. So take care.
Premiere must not be running
There does not appear to be a function to allow easy management of multiple sets of Preferences.
Settings used to be Sync'd to Creative Cloud but that appears to be withdrawn now.
You could submit it as an Idea under the 'Ideas' Tab on the Community
Hope it helps