Wifi download speeds considerably slower than upload EA6350v3

Hello guys,

I am using OpenWrt 21.02.1 stock image on EA6350v3 and recently I had to make it the main router in the network. The first difference I noticed is that the wired speed dropped from 940/600mbps down/up to 700/500mbps, not a big deal, I guess that's how much the SOC can handle.
The main issue is the wifi. On 5GHz I am getting 200/475mbps down/up.
I don't understand why. There is no interference, I tried changing channels, forcing 80MHz channel. I always get similar results.
Why is there such a big difference between download and upload speed?

Thank you!