I have a hAP AC Lite. I had bought it and a Groove for my 450 sqft RV and now use it in a 1500 sqft condo. I decided to revive the hAP and the Groove for more firewall and other controls as well as using the Groove as a backup Internet source and routing gateway, connecting to a phone as a hotspot, when cable Internet goes down.
Problem: Was getting horrible WiFi performance on the order of 5Mbps or less at times, lag, etc. Living in a condo I have lots of channel interference from other wireless routers in other units. Tried different channel changes, turning off various items, setting power levels, etc, etc. Nothing worked.
Solution: Moved the hAP away from a Bluetooth Soundbar. I originally had the hAP sitting within one foot from a iLive Bluetooth soundbar and Samsung TV. I moved it to a table and things got slightly better. After trying everything else, I decided to move the hAP to the slab wood floor (actually a table shelf just above the floor); literally 2 feet down. Now in my furthest room I get speed tests of 85Mbps wireless, which is little difference from Speed Test on a phone just a few feet away from the hAP. The hAP AC lite has no external antennae and the internal ones are likely not the best. That said, I cannot believe how much difference it made moving the hAP just a few feet. Maybe external antennae routers would be more forgiving.
Recommendation: Consider moving your wireless router / AP way from any devices that may interfere with it.