Windows 10: Find and focus opened app across multiple desktops

I use Windows 10 multiple desktops feature. Problem is I often have 4+ desktops, then it becomes annoying and time consuming to find where is the app I previously opened again. Oftentimes, I just give up and re-open the app on the current desktop rather than search for it, not ideal for resources etc. Is there a smarter way to find it?

EDIT: Ideally, I'd like to search by string, for example type 3-4 letters to bring up a short drop-down list of matching opened apps. I tend to avoid mouse use if possible, often I rather use the Windows key search feature (Cortana I think) to open apps rather than using the mouse to pick them from start menu.

Solution 1:

WindowWalker that is now part of PowerToys (which needs the .Net Core Desktop Runtime) achieves this.