To be honest my GX Eagle rear mech lasted 2 years. The rear cassette is a month older and I’m still on the original chain and it’s been used all year round in all UK conditions.
It’s really caused me no issues and only been indexed once, so have no problems spending a decent sum on a replacement.
So ordered the X01 Cassette and Chain from Bike Discount and it’s on it’s way from Germany right now!