So a friend of mine helped me figure out how to disable categorized favorites menu. If anyone is interested, here's how to disable it:
Disable the following mods:
1- CategorizedFavoritesMenu - [Favorites Menu]
2- Categorized Favorites Menu Oni Edition Version Widescreen - [Favorites Menu Addon]
3- CCFM - HoleyGrail
Disabling these mods alone still wont get rid of the categorized favorites menu, because, as it turned out, the installed SkyUI is basically a customized version which has CFM integrated into it, so basically install the latest SkyUI from Nexusmods, enable it and disable the old one. Also don't forget to put the new SkyUI in the same order as the last one.
Hope this will help you as it helped me.