Upgrade from RBK50 to RBK852 significantly drops network reliability and performance

I did the same upgrade recently, RBK53 to RBK852 - so one less satellite than I originally had.  Performance has been great as you say - with a blazing fast WAN connection close to 1.4Gbps using the aggregated ports.  Reliability has been solid as well. My friend and I have been doing Internet based jamm sessions during the pandemic using software that is like Zoom for musicians.  It is a difficult ask: to provide a realtime music session with reasonable roundtrip latency (less that 20ms) and low jitter and dropped audio frames.  We've only found two software products that can do a good job with this, Jamkazam and Sonobus.  Of course we'd been doing this with the RBK50 setup for most of the pandemic and have only recently been using the RBK850 but the sessions have been solid even over the course of a few hours with no drops, disconnects, nor any other router issues.  We also Zoom chat during breaks and that's been solid as well.  Beyond that, I have 3 Nest cams and handfuls of other IOT devices connected all quite solid. The Nest cams are the biggest tell as they will complain about connection issues and the outdoor cams didn't do nearly as well with the RBK50 and would often show weak signals even though they worked well enough mostly - but no problems like that now.

Of course every setup is different, but my experience has been very good so far.