4 new Chime Pros (2nd Gen) and still cameras go in and out all day

I have a 1st generation ring alarm, 1st gen doorbell pro, and 6 additional wifi cameras on the outside of the house. For almost 2 years, no troubles until I upgraded my router. Ring support claims that the 5ghz vs 2ghz has something to do with the now spotty nature of my camera connections and I installed 4 new chime pros (2nd gen) in addition to the current 4 chime pros and 2 ring extenders. My house is not that large - (relatively speaking, I guess) - it's under 3,000 square feet. The furthest camera has a "good" wifi connection. I only got the 4 new chime pros last week becasue last week's rep told me that I needed to get my cameras off the wifi and onto the chime pro network instead. He said the chime pros would extend and strengthen the signal sufficiently especially since the wifi seemed strong enough even without extenders. The ring alarm is exactly centrally located and the wifi router is one room off of center but only about 20 feet away (through one wall). All the monitored doors and windows are on the first floor and second floor - and none of them ever has trouble. the chimepros are all on the first floor and are all within 30 feet of either the router or another chime pro. The new chime pros are constantly (mainly the 4 new ones) going offline even though they show connection speeds (every one of them) of 55 or less . They'll be looking perfect and all cameras connected perfectly one mionute and then 3 cmaeras will go offline along with one of the new chime pros for no apparent reason. Literally minutes after they were all looking good. If I unplug/replug a chime pro, it'll re-connect but within half an hour, they usually start flaking out again. I thought maybe they were too close to each other, so I tried putting one in the basement and one on the 2nd floor - but that made no difference. I also tried unplugging one and then two of them to see if they were conflicting with each other, but that did not help. My last confersation with ring (yesterday) ended with the rep telling me to return the 4 new chime pros and buying an eero for $99. He swears that will solve my problem. I have doubts - and when I researched the eero, it looks like you need more than one, despite him telling me one was enough. I just purchased a brand new fios router (es3100) and do not want to replace it or add a "mesh" network to it. My furthest camera has a good enough connection to the wifi all by itself and there were no problems until I upgraded to include 5ghz. Can anyone offer any suggestions? I no longer trust Ring's support and I really want to get everyhting back in proper working order as it was prior to upgrading my router. Pete