A community to help people learn, install, set up or troubleshoot their home network equipment and solutions.
You only want one router on your network -- the one connected directly to your ISP/Modem.
Any other device after that should either be a network switch, and access point, or another router that is specifically set to access point mode.
If you attempt to use two routers in "routing mode" on your network, one of them will end up behind a 2nd layer of NAT, and potentially wreak havoc with gaming and any port-forwarding that you might have in place.
Any additional routers should be in AP mode or settings modified to run similar. A router performs specific routing functions so there can be 1 setup as router. You can just run a cable to a switch if that's all you need. Or a switch then add a WAP (Wi-Fi Access Pointl to the switch.
This may help clarify a bit for you, there's a lot there so kick back and learn
There’s no point buying a second router. If you are thinking it will offload some work from the first router, it won’t. An Ethernet switch may be all you need if you want to connect both devices to Ethernet.
The plan is either buy a whole new router to better support wired gaming, or some other option which would include the existing router. We want to keep wireless, but improve our wired gaming, hence asking if I can out a ethernet switch after a modem, before a router.
What you're describing will work, but the Mikrotik will be taking over from your Netgear as the router. The two PCs connected to the Mikrotik will not be able to see anything connected to the Netgear unless you change the Netgear settings to put it in AP mode (or whatever Netgear calls it).
However, Mikrotik routers are a long way up the learning curve from consumer gear. Have you looked into what's involved in using one of them to run a network? Are you comfortable you can deal with it?
I could learn, I wasn't aware it would be more than plug N play. I was drawn to the commercial gear because it seems like gimmicky.