Hello,
Have you checked the Group Policy settings for Search?
Here are the dev Blogs on Search, there is a lot of detailed information in them, som eof which may be useful in tracking down or resetting Search.
https://devblogs.microsoft.com/windows-search-platform/
You may want to check the search database files.
By default, Windows.edb or Windows.db is located in the C:\ProgramData\Microsoft\Search\Data\Applications\Windows folder.
You can delete them, but stop the Windows Search Service first.
You can use Computer Management( right click start and choose Computer Management;
The startup type should be automatic.
Thanks
Darrell