[Tattvadarzin]

I edited my post to add ^\\(?!Library$) which employs negative lookahead, but you may not have seen that.

Thanks for the Python hint. I was using regex cribs and test sites (I used to use them before I retired - they are so useful. Back in the day, the internet didn't exist so all my hand rolled regexes were tried with great pain.)

I am stubborn enough to try my way. I admit I do not understand the bit about reinstalling. If I have it right:
Change .conf file
Disconnect and reboot.
Kobo removes old info, rescans and adds to database.
Connect to PC
Extract one click zip to Kobo root.
Disconnect and reboot.

Things look better but I see 3 png files in My Books: kfmon, koreader and plato. I will need to redo the above as I am not sure which regex I used.

I don't understand why I need the reinstall unless Kobo physically removes files on the rescan.

Anyway thanks for the help. I like to understand what is going on under the hood.