New patches usually mean that issues arrive along with the update, and Baldur's Gate 3's Patch 7 is no different. The mod manager was one of the biggest additions in the patch, but some players are reporting that it is currently broken.
Baldur's Gate 3 Patch 7 – How to Fix Your Mods! BG3 Mods EASY guide for Patch 7!
There are two solutions you can try to get the Baldur's Gate 3 mod manager working again, and the first is to install the ModBrowser as a mod itself. You can find this in the mod manager, and if it doesn't show up then make sure you have the latest version of the mod manager installed.
If that doesn't work for you, follow these steps to try and get it working:
Don't forget to backup your mods before doing this, if it works for you you can simply reinstall them.