Control + Scroll Wheel doesn't work for zooming in version 13.
In what Panel are you expecting this to happen?
Bridge has never had "zooming" into a photo. It has a Loupe feature in the Preview Panel. The Preview Panel will show up to 100% of any image, but no larger than will fit into the current size of the Panel and never any more than 100%.
In the content panel, Control + Scroll wheel = zoom, in every version prior to version 13. I've just reinstalled version 12 and it works. Another thing that is immediately broken in version 13 is when you press Control F for Search. In all previous versions, it would place the cursor in the criteria field so you immediately type a new search. In version 13 it places the focus on the new giant blue button to OK the search. So if you're going to type a new criteria, you have to either use the mouse, or tab 4 or 5 times to place the cursor in the criteria field. For me, Bridge is really just a glorified image finder/viewer but the whole point of it is speed. I don't really use any of its many other features so I've reverted back to version 12.
Another thing about version 13 is the color contrast is terrible now. Adobe managed to get Photoshop and Illustrator, etc very nice. Soft on the eyes. Bridge is stark contrast. I have a problem with my eyes so that I can't view white text on dark background very well. I'm told that many people have the same issue. I don't know why Adobe changed this but I hope that they don't do the same with Photoshop and Illustrator. I don't need Bridge. I can probably do just fine with Windows Explorer, I just don't like having to resize the windows. I need a tall narrow windows for all of my work, but for file searches, I need a large wide window so I can view images and files at a large size.
OK, zooming in the Content Panel. Yes, this needs to be fixed.
I COMPLETELY agree with you about white text on black background: Fortunately, this can be fixed by going into the Preferences, selecting the Interface Option, and selecting the lightest option. No idea why they didn't have the four options they had before and now it's down to three. But the white does give you what you want.
I could survive with a white UI, but what I really want is for it to look exactly like it did in version 12, as far as contrast goes. Like Photoshop and Illustrator. Dark UI, but not such stark contrast. In the meantime, I'm back to version 12. When that is no longer supported, I'll go back to using Windows Explorer.
The mentioned issue is fixed in the latest patch release #188.8.131.523. Please install and confirm if that fixes the issue.
You can refer to the issues fixed in the patch at the following link https://helpx.adobe.com/bridge/kb/fixed-issues.html