Did you verify the Privacy settings wasn't unchecked for Strong Password settings?

I don't use this feature, but I noticed on my test page at https://www.jeffersonscher.com/res/logintest.html that I need to right-click the password field and use a menu item to generate the suggestion. I think maybe it used to appear automatically (I was ignoring it). Do you have this right-click menu item at all?

No, it doesn't even create that popup after clicking the context menu option. And I did check the settings to make sure that Firefox SHOULD be able to create password suggestions.

On a completely clean alternate profile it works as intended, which led me to conclude that there is an appdata file in my main profile that is bloated or slightly corrupted to the point this specific feature is broken.

I should elaborate that I tried troubleshoot mode (disabled all customization and extension) and it still did nothing.