So it sounds like this isn’t an issue with VR preview being greyed out, since you can press it. But rather an issue with the connection after that point.
Suggestion for this issue: Do you get Oculus Home loading correctly? If so. Try taking your headset off and then on again when you have the black space with blue circle, it sometimes helps when the headset retriggers being worn. Also, end VRPreview and make sure the Oculus menu (grey zone for me) loads, and then try again. I also have some hiccups here sometimes but it always kicks in after some finagling… like having to reset guardians over over and over… it’s just one of those things that hasn’t been smoothed out yet.