Try few Safari maintenance steps.
Go step by step and test.
1. Startup in Safe Mode: https://support.apple.com/en-us/HT201262
Login to your account.
Launch Safari and test.
To exit Safe Mode, click in the menu bar and choose “Restart”.
Launch Safari holding the shift key down and test.
2. Clear all website data
https://support.apple.com/guide/safari/manage-cookies-and-website-data-sfri11471/mac
3. Enable Develop menu, click Develop in the menu bar and then Empty Caches from the dropdown.
https://support.apple.com/guide/safari/use-the-developer-tools-in-the-develop-menu-sfri20948/mac
Safari will remove all favicon as well. It will be replenished as you visit those sites again.
4. Disable extensions and test.
Safari > Preferences > Extensions
Uncheck the box beside name of the extension.
https://support.apple.com/en-us/HT203051