So, the only Chromebook/Intel ac-7260 advice I found on the Internet was from UBNT and how to adapt their config.properties.
In previous tickets, an Acer Chromebook troubleshooting case, says to avoid the 5G DFS /radar channels, and the customer
immediately saw improved performance.
If Ruckus can help, I've found a bug ER-3229, for Chromebook periods of not passing traffic or very low throughput (on R710),
awaiting further engineering feedback, with a target of ZD 9.12.2, SmartZone 188.8.131.52.476+.