Insight Instant Wireless AirBridge not giving full speed (WBC502)

Greetings!

I have a WiFi network set up extending my Comcast Business Internet (600/45) out to a small barn office using a pair of Netgear Insight Instant Wireless AirBridge (WBC502) units. The cable modem in the house is a Motorola MB8600 DOCSIS 3.1 and the router in the house is a Motorola AC2600 4x4 WiFi Smart Gigabit Router with Extended Range (Model MR2600). 
The AirBridge is plugged into the the router. At the barn, the. AirBridge is plugged into a Huawei WiFi AX3 pro WS7200 Wi-Fi 6 Plus Quad-core Router Mesh WiFi 6 System. While what comes into the house is 600/45. Out in the barn office I only get 228/41. The AirBridges are set up as Master/Slave.

Questions:

1. Anybody know of a reason why the highest speed isn't attainable?

2. My Zoom meetings tend to have occasional freezes, why?

Zoom says all it needs for HD quality meetings is 3.5 mbps download and 3 mbps up. I do have 5 Blink cameras on the the 2.4GHz network on the house router. My work is on the 5GHz network (including Zoom). Maybe I should try disarming the Blink cameras during meetings...

Thanks in advance for any comments.