mystery router following me !

I bought a new 802.11 AX wifi adapter to match my new AX router for my i7 computer, it plugs into a PCIe slot on the motherboard, it has the same little intel ax200 wifi/bluetooth board that my new i9 computer uses, ok it works really good, but here is the problem, if it’s alone on a 5G channel, I get the top speed 2.4 Gbps, but there are two other routers that keep following my channel where ever I go, it’s not random, I have tried every frequency from 36 to 165 they follow me to all but a few, there are some frequency’s their router won’t follow me to but my 3 ROKU's, my phone and other devices won’t see my 5G router on those channels, (I’m not sure why that is,) as soon as the other routers chang channel to match mine my wifi speed drops to 1.2 Gbps  (I have several computer set up to watch what is going on.) I never see it go up to 2.4Gbps when I'm not alone on a channel, what is going on here? why do the other routers follow me? the other routers are close  to mine their signals are as strong as mine at my computer, that's probably the reason my speed is getting hammered. this is so frustrating.