yes 86u is way better than ax3000/ax58u
ignore ax56u
lets agree getting speed plan upgrade is easier now
time is going as fast as 1gbps now, and unifi 800
dont be fools by AX3000 rating
i believe not a lot of people is using AX device right now, even it becomes norm, AX devices or wifi STILL can do AC protocol
then lets see the spec
AX3000 speed on AC is up to 867 Mbps
ac86u speed on AC is up to 2167 Mbps
for now and for whole family as a whole, AC is the standard protocol for everything
pc, phones, table, tv, tvbox, tv sticks
being an AX device itself isnt future proof right now
especially AX58u because it is not a wifi 6 certified router
when AX58u came out wifi6 is still in draft form
so AX58u certainly isnt future proof at all
the only wifi 6 certified router from Asus as of now is AX6600 and Ax88u
my advice is, for now, if budget allow and your speed plan is high, get AC86u
since we are talking about Asus, any of these router are capable of aimesh
getting AC86u assure performance of your unifi and if really want/need AX router in the future
then get the better and newer AX router by the time comes and use 86u as a mesh node.