A shot in the dark here, but are there any tools (whether ATC add-ons or otherwise) for MSFS that display where rendered AI is flying in your area?  I've used various tools for other sims where I could look at the map and see, "oh, there's a plane heading my way" and then I would visually try to spot it when it appeared to be close.

Little Nav Map??

Avliasoft EFB

I believe the v key will bring up the default map and if I'm not mistaken it shows other planes in your area.

 

The default map shows traffic but you have to zoom in a click or two.

LittleNavMap displays AI planes and ships.

FS-FlightControl shows other aircraft on the map.