Hi Gordon,
Your primary router is always the one your incoming internet line connects to on its globe (WAN) port.
It's hard to tell for sure from your description if this is the case, but you want all of your other routers/points to be behind your primary router. Some examples:
Modem → Primary Wifi router → Switch → Point(s)
Modem → Primary Wifi router → Switch → Point → Additional point
Modem → Primary Wifi router → Point → Switch → Point → Additional point
More details:
Hardwire Nest Wifi Pro, Nest Wifi or Google Wifi with Ethernet - Google Nest Help
I would also confirm all of your routers/points are hardwired not just some of them. If you only hardware some of your routers/points, this is much more likely to cause problems that are very hard to diagnose. The primary one being that if one of your non-hardwired Wifi points can establish even a weak connection back to your primary Wifi point it will do that, over connecting to an intermediate closer Wifi point, because it prefers the least hops to get back to the primary Wifi point. This is also the reason Google recommends placing your primary Wifi point as close as possible to the centre of your home.
Where to place your Wifi devices - Google Nest Help
Assuming you're good on both of those points, I'd recommend checking all your cables and connections, even try swapping them for known good cables. Cat6a cables are known to be less flexible and have a larger bend radius than previous generations of ethernet cable, meaning they are more prone to damage from excessive bending. If a Cat6a cable is bent too sharply, it can kink, damage the internal wiring, and degrade performance much like what you described.
Hope this helps!
