Using +F you used to be able to open a search dialog.
I recommended WinKey+F this as an alternative to the start menu search, which didn't work anymore for a blind person using a screen reader. He told me that after trying this, he got "something about signing in and when I hit enter, nothing happens". Starting a Windows 10 VM and trying myself, it turns out they changed this to the "Feedback Hub".
What is the new shortcut? I tried +F3, F3 by itself on the desktop, and Ctrl+F on the desktop.
An alternative I just thought of while writing this post is two steps: +E to open explorer, then Ctrl+F to focus the search. This seems to work when trying it. Is this how you are supposed to do it now?