Slow and Sluggish Illustrator UI - Especially When Working With Text Panels

Illustrator has become extremely slow recently overall, but it is especially noticeable when working with text.

General UI actions feel sluggish, and anything related to text is much worse:
- Opening the Character panel takes several seconds
- Selecting text has delay
- Changing text parameters is slow
- Text-related panels respond very late

In addition, Illustrator itself takes a very long time to launch and fully load.

My PC is strong (RTX 4060, lots of free SSD space, updated drivers, latest Illustrator version), so this does not seem hardware-related.

What I already tried:
- Updated GPU drivers
- Cleared temp/cache files
- Reset Illustrator settings/preferences
- Disabled GPU Performance
- Tested on new empty documents

Has anyone else experienced this recently?
Could this be related to fonts, Adobe Fonts sync, recent Illustrator updates, or some known bug?