Currently, VRService.AvatarGestures does not support crouching for VR users and can cause issues for users with taller or shorter avatars. Plenty of my avatars do not work well with VRService.AvatarGestures since the head is above my real head, causing me to have a view from my chest.
Currently, the only workaround that I can use is to use OVR advanced settings to move my camera slightly higher to be level with my head at all times. This means that I must stand up tall at all times and can be very bothersome as someone used to games like VRChat and Blade and Sorcery that give you a full range of motion on the Y axis.
I do understand Roblox focusing on compatibility, but I do think that compatibility is already achieved when you have VRService.AvatarGestures disabled, so having the crouch will not be an issue in terms of compatibility (plus, VR experiences normally do not restrict the body on the Y axis and can be jarring for many users)