Hi @simplybright,
Thanks for sharing the details. Illustrator should normally refresh newly added system fonts without needing a restart, so this behavior isn't expected. Please try resetting Illustrator preferences (https://adobe.ly/3VShctG) and see if that helps. Also, ensure you’re installing the fonts for 'All Users' in Windows rather than just your current profile, as that can affect how Illustrator detects them.
Additionally, try signing out and back into the Creative Cloud desktop app to refresh syncing. If the problem continues, clear your system font cache using the steps here: https://adobe.ly/3VPedCr.
Once done, restart your system and test again by installing a new font while Illustrator is open. Let me know if the fonts still don’t refresh automatically, so I can check this further.
Looking forward to your update.
Abhishek