I noticed that the official FAQ has been updated with this although I'm not sure how long ago was it:
Does PS5 support VRR?
PS5 hardware supports Variable Refresh Rate (VRR) through HDMI 2.1. After a future system software update, PS5 owners will be able to use the VRR feature of compatible TVs when playing games that support VRR
PS5: The Ultimate FAQ
Everything you want to know about PlayStation 5, all in one place.
blog.playstation.com