Upgrade from RBK52 to RBK852: Many more "no signal"/connectivity issues

This is a continuation of discussion started on "AC3000 mesh wifi system (rbk50) vs ax6000 wifi mesh system (rbk852)". 

Here is my initial post on 2021-01-29 09:11 PM:

"I just upgraded my RBK52 to an RBK852. Everything was the same. Same location for the satellite and the router. Both the 52 and 852 are in AP mode. My router is a Verizon G1100. I upgraded because I have 20 - 30 wifi devices depending on time of day and which devices are running (washer/dryer/Generac). I live in a townhouse community. The wifi is crowded. I have 10 wifi security cameras. Some are dual band; some are single 2.4 Ghz bands. Three cams are inside so only are running from dawn to dusk. I was attracted to the RBK852 since it could handle upwards of 60 to 100 wifi devices. It was based on wifi 6 chip set, with must more throughput and more antennas.
The RBK52 worked well most times. Occasionally, some cameras would drop (no signal) and I attributed that to increased wifi activity in my neighborhood. I decided to purchase the RBK852 to set up for the future with wifi 6 cams and other devices. The install went well. Since I already had the RBK52 in place I just needed to set up the RBK852 the same way, including the SSID/PW. Since the change I have a huge increase in the number of camera drops. I need to do more research as to why this is happening. I am surprised this is happening. The new satellite is the source of most of the drops. (Note: a drop to me is a loss of signal/connection. The connection is reestablished quickly, but the loss is noticeable. All my cams record 24/7 on Blueiris and they FTP to send pics when motion triggers an alarm. The RBK52 handled this. The RBK852 struggles with certain cameras. None of the cams have moved. I did not expect this. I am running the latest firmware (V3.2.16.22_1.4.9). More research from me."

Since then I have received many suggestions from FURRYe38 , vajim , Mstrbig 

I will update everyone as to where I am right now based on the suggestions so far:

Notes/Status:

1. The RBK52 has been running smoothly for nearly 3 years now. 

2. I live in an end unit of a 3 unit townhouse. It is two stories with about 2100 original sq ft and an additional 176 sq ft sunroom addition. The house is on a slab, no basement/crawl space. There is a lot of wifi activity among all the units. I use NetSurveyor to monitor the various channels across both wifi bands.

3. The RBK52 router was positioned second floor front of building. The satellite was stationed in the sunroom, first floor. The distance between then (not accounting for the angle first floor to second) is approximately 40 feet. 

4. I decided to upgrade to the RBK852 because I have any wifi devices and I get some "No signals". These I attributed (with no real science) to the heavy wifi in the neighborhood. Based on the RBK852 specs, it can handle 60 - 100 devices.

5. The intention was to set up the RBK852 just like the RBK52. Both are "AP Mode". The Verizon router G1100 has both wifi bands tuned off. It is acting as the router. My internet plan is 100/100. I have no issues with speed. I would change the setup to RBKs do the routing and set the G1100 to bridge mode, but I would lose many Verizon TV functions like the guide, etc.

6. I set up the RBK852 as close to the RBK52 as possible. There were a couple options that were different. I don't remember which ones. 

7. On Wednesday, 2021-01-27, I switched the units. The RBK852 came up no issues and I was off an running. Over time though I noticed a huge uptick in my "no signals" on some security cams. By Friday I decided to switch back to the RBK52. See pic 2021-01-29. 

8. Picture 2021-02-01 was from today. Not exactly the same number of hours butt it will give you a clear idea of the huge difference between the 2 systems. The RBK852 pic is after about 48 hours and the RBK52 after about 36 hours. Again, the systems are nearly identical in setup and location.

9. The four cams are the four most important to me. Two are in the front of the house (BFEast/JTWest) and two are in the rear (JTSouth/FCBack). The other cams are supporting and provide other views. All four are single band 2.4 GHz and are outside. 

BFEast: 0 RBK52, 275 RBK852. JTWest: 9/90. JTSouth: 0/222. FCBack: 0/152. Pretty wide discrepancy.

10. All total I have 13 cams. Four are wired and don't count here. Nine are wifi. 

11. Here is a list of most of my wifi devices. Not all are active all the time. 2 Nest thermostats, 1 Ring doorbell, 1 washer, 1 dryer, 1 Generac, 6 exterior cams, 3 interior cams, 2 iPhone 11s, I iPad mini, 4 laptops, 1 Roku and 1 robot vacuum.

12. There is no issue with internet speed up and down. The backhaul of the RBK852 is faster than RBK52.

Bottom line, the issue is the number of "no signals" or loss of connectivity with these cams.