If you own Valve Index lenses and cannot stand the glare, you could try replacing the lenses, albeit at the risk of some distortion and a reduced field of vision. You can simply buy a smartphone VR headset, take out the lenses, and model an adapter for them. You can print this model and then tinker a bit with the distortion.
The glare is sure to be gone, although there may be a bit of pupil swim, a reduced FOV, and/or distortion, but most users can live with these.
If you would like to try out this modification, you can get a pair of either BOBOVR or VR Shark X6 lenses. These headsets look very similar and seem to be simply marketed under different brand names in different regions. You may also get them as second-grade goods, so ensure to enquire from the distributor.
See the distortion profile of these lenses here.
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