I have an ont 612 with a coaxial connection to a m1424wr router. I connected my Xbox one via a cat 6 cable to the router and got download speeds of 120 Mbps and even peaked at 240 mbps for a second but I thought the moca connection was limited to 100 Mbps? I was thinking about getting the g3100 for better wifi speeds.
MoCA 1.1 is capable of 175Mbps maximum. Are you still on the legacy 100/100 plan?
If so, you don't need a G3100 for WiFi improvement. G3100 delivers 900Mbps+ on 802.11ax. A G1100 would fulfill your needs better. G1100 has 802.11ac, so can achieve 300Mbps+ on 802.11ac.