I have to side with
@Tech9
The AX86U seems to be more sensitive in my environment, though my AX86S antennas (set or individual stems) are also "superior" out of the box, even improves range on my older GT-AC2900 which has the same general design. It's quite odd.
GT-AX6000 doesn't work well for me in the same regard, but I can't exactly swap antennas to that model..
At this point, it likely has to do with local EMI and power/grounding influencing products in my home. I don't really don't see any other logical explanation.
In regards to alt models like AX
68U, I'm concerned about the radio design and how it functions with the main CPU.. Seems to be weaker or stress main CPU use (to a higher degree) versus last gen 3x3 ACW2 BCM4365E (which has a confirmed internal 800mhz A7 core) on my GT-AC2900.
At least this happens with the 6710 radio on both AX86U/S. I wonder if the core is weaker or removed and loaded off main CPU. Could make an argument for SoC variants being superior since the Tri/quad A7 SoC @ 1.5ghz (1.7ghz for newer gen 2 products) look to be pooled (Radio+CPU).
Maybe I'm wrong and the 6710 has its own internal high clocked A7 like BCM43684 and 675X SoCs. I really wish there were public datasheets.