Yes
Yes
Many users report that IGMP proxying improves stability while gaming, which aligns with your usual approach. You’re currently enabled and haven’t faced any problems. Whether it’s useful for you depends on your specific situation—consider checking recent reviews for more tailored insights.
I've turned it on myself. For me, it's the quick way to fix all the problems I had with my router. Results might differ. Keep it on unless it affects performance or response time.