"Your rendering Device has been lost"

What I did to fix this, was made a lot of space for overwatch to run. What I mean by this is to clean out your computer as in make space in your hardrive delete anything you dont need. I had 78 gb left out of 930 gb. I removed a lot of videos by geforce experience deleted a lot of pictures and downloads and a lot of other things.
worked for me

These steps may help:

What I did to fix mine was I disabled Windows 10’s Xbox game bar overlay.
I use Nvidia. Hope that helps.