Although not directly related to OpenWRT... I am guessing at a minimum the AX3600 is quite popular with the OpenWRT crowd.
Has anyone used both of these side by side?
Which has better range?
I am debating swaping out one of my AX3600s for a Redmi AX6000 due to the 2.5gbit port (...and I guess 4x4 on the 2.4ghz band). So far I am quite satisfied with the range of the AX3600... I have a few clients quite far away, through more than one concrete floor, and they are able to associate no problem and I have yet to see the connection drop. Wouldn't want to downgrade that.
Given that the devices are very different, even if they are roughly targeting the same audience, it's very hard to guess.
On the one hand you have QCA vs Mediatek, on the other hand you have redmi vs xiaomi (redmi branded devices tend to save on shielding, RAM/ flash and similar things, compared to the xiaomi branded ones).
While the wired side should be better on the redmi ax6000, you will have to actually test the wireless side against each other to come to a conclusion… I wouldn't expect major differences in terms of range and throughput over the range, but even small differences might make- or break it towards the edges of your reception.
That assumes there is only one client. On an AX6000 you can do that with two clients at once.
AX6000 is more future proof.
I don't have an AX6000. I do have a Banana Pi BPI-R3, and two BPI-R64s with mt7615 cards, which basically gives them all identical wi-fi chipsets to the AX6000. The range on them is fantastic. I don't have an AX3600 to compare to.
The other benefit is that the AX6000 has WED (Wireless Ethernet Dispatch). That reduces significantly the CPU usage during periods of high usage.
100% - it's really hard to give good comparisons when most people don't have both. Even people who do, antenna placement and home layout can actually make one better for you, but the other better for me.