Post your settings for the following:
uname -a
cat /etc/config/wireless
Take a look here and see if it’s helpful:
Anywhere in the 500-600mbps range is great for a wireless AC connection with a 2x2 client. This is an appropriate rate for a 2x2 client once you take in to account wifi overhead and radio physics- here is a good read on wifi 5 and hype vs reality (especially look at the PHY chart): https://www.duckware.com/tech/wifi-in-the-us.html#wifi5
I am running more aggressive ondemand CPU settings, Irqbalance enabled, and my wifi settings are below (prime number beacon interval, 802.11r enabled, software…
Make sure software flow offloading is turn on in your firewall. Post your results for hardwired versus 5ghz / 80Mhz wide channel for speedtest.net and fast.com .