Hey there, dmaguire,
Welcome to our Microsoft Community.
I understand that sometimes troubleshooting can be a bit time-consuming and the fact that the issue is still not resolved can be frustrating. Your continued patience and cooperation are highly appreciated. I noticed that you have tried a variety of methods and appreciate the efforts you have made so far. If you have not tried creating a new index, we can go ahead and have a try.
- Press Win to open Start Menu and type in Index
- Click on Indexing Options
- On this next screen, hit Advanced > Troubleshooting > Rebuild
Windows will take some time to rebuild the search database and may disable search for a short period of time.
In addition, regarding the Outlook search problem you mentioned, the forum also has a special outlook section, where there will be outlook experts to assist you with outlook index problem.
Thank you for your time and effort working on this issue. If there are any updates or changes, please do not hesitate to let me know.
Have a nice day and stay safe!
Sincerely,
Olivia - MSFT | Microsoft Community Support Specialist