I’ve just bought a brand new hAP ax³ a few days ago, and connected its 2.5G port to my ftth router (600/300Mbits) and then i’ve connected my PC wirelessly to hAPs 2.4GHz wifi with default password that is provided on the hidden sticker. Speedtest immediately bumped up at 280Mbits download. I was soooo surprised and happy about that 
. And it worked like that for 2 days until i’ve decided to upgrade ac3’s packages from 7.8 to the latest. So now, I just can’t get that speeds again. After days of trying with different configurations never again was i able to go above 90Mbits. I have tried everything, also, i’ve tried reverting to the older packages like 7.8, reseting the configuration, bla bla bla. days have passed and i still hate myself for not being able to fix this.
Also, windows reports 400Mbps wifi connection established.
What do you think the problem is? 
/interface wifiwave2
set [ find default-name=wifi1 ] channel.band=5ghz-ax .skip-dfs-channels=\
10min-cac .width=20/40/80mhz configuration.mode=ap .ssid=MikroTik-3A8393 \
disabled=no security.authentication-types=wpa2-psk,wpa3-psk
set [ find default-name=wifi2 ] channel.band=2ghz-ax .skip-dfs-channels=\
10min-cac .width=20/40mhz configuration.mode=ap .ssid=MikroTik-3A8394 \
disabled=no security.authentication-types=wpa2-psk,wpa3-psk