I'm having the same problem on my RS300 with firmware V1.0.1.90

That's weird, I posted a comment on the thread below, but somehow that thread is now locked and my comment is its own thread.

RS300 Wifi Lag Problems | NETGEAR Communities

At any rate, when I'm on a video call over wi-fi on my new RS300, there is a lot of lag. It's better on the 6 GHz band, but pretty bad on the 5 GHz, even when my laptop is inches away from the router. Not all of my devices support 6 GHz, unfortunately. My old router was a Netgear R7000 and it never had these issues.

As mentioned above, the firmware version is V1.0.1.90.

My cable modem is a Netgear Nighthawk CM2050V-100NAS. The cable from the modem to the router is the one that came with the RS300. I'm not sure how to tell what kind of cable it is.

I manually updated the firmware to the V1.0.1.90 version to see if it would help, but no luck. I did not do a reset/from-scratch-setup after the firmware update.