Top priority: Did you try to disable AC Mesh/AirTime Fairness on your NanoStation?
Other tips: If not: Reduce your NanoStation Loco M2 to 20 dBm or less.
Last point, I’ve found that channels 1 , 6 and 11 are more stable with EVCS.
I do not recommend using EVCS w any good IT mgt like Ubiquiti.