The board of your version is the same one as the chinese one, in other words, the one that has the amplifiers as you can see here:
This is a picture of the chinese board, and the number on your board and this one are the same = AM1WS7200M
Here you can see the amplifiers themselves:
2.4 Ghz = https://ds-blobs-4.cdn.devapps.ru/20504303/AX3Pro-24.jpg
5 Ghz = https://i.imgur.com/M1HIGW3.jpg
The boards that dont have the amplifiers have different board number like this one:
https://ds-blobs-3.cdn.devapps.ru/20503910/AX3Pro-RU.jpg
Which is AM1WS720020M and as you can see in the picture there are no amplifiers for the 2.4 ghz.
So, are you sure there are no amplifiers in the router you got? How did you test the wifi 5 Ghz? Which device? Cause the client makes a big difference too, its not just the router!
Like in my case where i have and AX6000 from xiaomi and on my mi 8 i get excellent wifi range and speeds on a big house, but a family member with Mi A2 lite have much worse range and speeds!