Let's try a clean reinstall.

Download a fresh Firefox copy from https://www.firefox.com and save the file to a location of your choice.

Uninstall your current Firefox version and remove the Firefox program folder before installing that copy of the Firefox installer. Don't remove personal data when uninstalling.

It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.

You do not need to create a new profile, that is not necessary for this issue.

Have you tried reinstalling Firefox?