I too think Zorin is amazing, which is why I am using it. We also have other members excited for OS 16 LITE's release, such as Jeff! Some people prefer XFCE because of its customisability.
While other's prefer XFCE because its less of a load on hardware. You could almost run XFCE on a potato, although I think BionicPup is better served for a potato computer.
Yes, there are extensions to improve the Gnome experience, I use them myself, I have a post on here about Gnome extensions...
You got to make sure you have your Gnome integration enabled in your browser before installing and using extensions though. And yes, extensions can be chosen and configured through Gnome-Tweaks as well, good job on being informed!
The sheer amount of dissatisfaction you have for Gnome however, is what made me think the best solution for you, was to switch to XFCE desktop. Aravisian is also correct that I Cinnamon might be a good pick as well for you, for a desktop experience.
I too also agree you could simply wait for OS 16 LITE to be released as well. It will have XFCE desktop already loaded and configured for operating pleasure. The choice is up to you, and thats the beautiful thing about Linux, your choice, not a companies.
I wish you luck on your adventure, just know, that we were at the ZorinGroup forum are here for you. Thanks also goes to @Aravisian for helping you with this, I really appreciate it!