The BNext VR Headset is the best overall VR headset for your Galaxy S21. It is compatible with smartphones between 4″ and 6.3″ screen size, which would work with the latest iPhone 12 that is 6.1 inches and the Galaxy S21 at 6.2 inches.
|BNEXT||VR Headset Compatible with iPhone & Android Phone||Check Price on Amazon|
|OPTOSLON||Virtual Reality Headset, OPTOSLON 3D VR Glasses for Mobile Games and Movies||Check Price on Amazon|
|Google 87002823-01 Official Cardboard- 2 Pack, Brown||Check Price on Amazon|
|MERGE||MERGE VR Headset - Augmented Reality and Virtual Reality Headset||Check Price on Amazon|
|FEEBZ||VR Headset Compatible with iPhone & Android - | Virtual Reality Goggles for 4.7”-6.5” Cell Phone||Check Price on Amazon|