Does 17.01.4 support MU-Mimo?

I running 17.01.4 on a Netgear R7800 and I am experiencing upload speeds at a third of download speeds. The WAN link is symmetrical (FIOS).

Does 17.01.4 support MU-Mimo? If it still doesn't, great. If yes, how do I disable it?

PS: iperf tests report 120 Mbps from router to laptop and ~96Mbps from laptop to router. WAN speed is ~75Mbps both ways, but speedtest reports ~30Mbps DL and ~25Mbps upload

TIA