Regularly?
This season we have used two formations; 4231 or 352. This is further backed up by
whoscored.
As you said, he used a diamond once against Everton, which wasnt at all convincing and ended up going back to a 4231 later on in the game.
It might be the case he does experiment when the season restarts, although I think theres an element of risk there, simply because we were doing really well before the pandemic hit.
If Ole played a different formation before Pogba's injury, I could understand people thinking he'd possibly go back to that, but Pogba played in a 4231 at the start of the season. Difference is, we now have Bruno as a 10, as oppose to Lingard/Pereira.
Having said all of that, I do think the squad of players we have allows for quite a lot of flexibility. The diamond does look quite tasty. I just hope Ole doesnt sacrifice balance by trying to fit all the best players into our team.