I just had a similar issue with Xcode 16 and iOS 18. Turns out I had updated the main app 'deployment target' to 18 but the widget to 18.1. You could install the app but the widget was missing from the widget search. I know olvrptz said his widget shows up on is simulator so this may not have been his issue, but just one to check in case it's yours.

Also be aware that if the title of the tab you are in is in italics, you can double click the tab - then it will become 'normal' font text and will NOT be replaced. Making a change in a file will also change the title from italics to normal and stop it being replaced in the same way. Tabs were driving me insane till I worked this out. Dont know if there's a keyboard shortcut for the double click?

Did you ever hear back or find a workaround Eric?