My switch makes everything break?

I’ll attempt to be as brief as possible. I’m on staff at a church directing all things tech. My original trade is sound engineering, but these days much more falls on my plate. Today it’s our network.

Setup/flow:

Modem -> Switch

Switch feeds a wireless router that is mostly used for wireless control of various systems through iPad apps.

3 iMacs are also connected to the switch for live streaming purposes. 1 runs OBS, one runs ProPresenter (which then connects back to the OBS iMac for NDI video output), and 1 runs lighting.

Everything has always worked fine, outside of constant issues with Cox. We lease a building on another church’s property and have always just used a split from their network for ours. We got tired of this, and today has Cox come out and set us up with our own drop and modem.

Now things don’t work like they did. It seems my switch has decided to make things not work. Anything connected to the switch gives me a “self assigned IP address” issue and doesn’t connect to the internet. If I take the switch out and just use the router for all connections, everything works fine.

Why would the switch be doing this, and what can I do to fix it? I’ve googled endlessly and can’t find a solution. We are using:

NETGEAR 8-Port Gigabit Ethernet Unmanaged Switch (GS108) - Desktop, and ProSAFE Limited Lifetime Protection https://www.amazon.com/dp/B00MPVR50A/ref=cm_sw_r_cp_api_glc_fabc_aAb3FbJ8CP3JW?_encoding=UTF8&psc=1

Is there a different switch I should try?

Thanks for any help.