I don't have the AC86U but instead have 3 AC3100's & a 4rth as a spare. One is a mesh router and 2 are mesh nodes. If my units are any indication of Asus' quality than the AC86U should have few, if any, issues.
I have two 4k Roku TV's, one 1080p Roku stick, a FireStick, an Xbox, 5 laptops, 4...