yes
you won’t need a 3070 minimum like for a Varjo Aero but you’ll still require something better than a GTX 980 for decent fps.
I’ve never owned an Index but I’ve never heard of problems with AMD.
imo I don’t think so. The best all round VR headset is the quest 2 as it’s so versatile…but if you’re only using sims some will say the G2 is best as it has high clarity. The best for MSFS is the Varjo Aero but that is very high price.
What are your specs? I would advise a quest 2 or a G2 if you have the pc (gpu mainly) to power them.