Sleeping on tummy

My 21 week old learnt to roll from back to tummy this week, I was so excited that I got it on video!

However with this great milestone comes another obstacle, he likes to roll onto his tummy while in his sleep and wakes up almost immediately crying. I know they say “if they can roll over they have the ability to roll back” but as I watch him on the monitor he doesn’t know what to do to flip himself back.

I’ve tried countless times to get him to nap on my chest but he would never stay. Always wanted push up to look around.

Any suggestions on how to get him comfortable with sleeping on his belly?