There are far too many variables to tell online.

Find someone that can come and take a look at your specific home and seek their advice.

I think what you are really asking is “how can I find out what other Internet providers offer service at my location”

And the answer is to go to this site and enter your address:

https://broadbandmap.fcc.gov/home

Either of those would work fine.

Keep in mine that your wired devices need to connect to to your router as well - the router isn’t just for wifi, in fact wifi is a *secondary* function of a router.

Did you give the ISP the DOCSIS MAC address of the modem?

If not, it will never work, they have to register it on their network before it will be allowed to connect.

One, I would generally not recommend a modem/router combo at all, but instead separate devices.

Two, you only want a cable modem if you are subscribed (or are going to subscribe) to a cable ISP service. A cable modem would be absolutely useless for a fiber or VDSL service. (And if its a DOCSIS compliant modem, it should work with any DOCSIS compliant cable ISP)

So the first step before deciding what (or if) device you want to obtain, is to at least be certain what ISP/service you’re going to subscribe to.

And often, unless you have very specific needs and know exactly what you’re doing in advance, you’re usually better of starting by using whatever device the ISP you subscribe to provides, and THEN consider whether you need something different or additional. And if you’re seeking advice on reddit at that time, you should be sure to give the exact brand and model of the ISP provided device.

All that said, if I was going to buy a cable modem either to replace an ISP device or for a new service, I would probably get something like this:

https://www.amazon.com/ARRIS-SURFboard-SB8200-RB-Approved-Spectrum/dp/B07M8BNVSD/

And I would continue to use my existing wired router and separate wifi AP. I can see it probably making more sense for most end users to get a router with a wifi AP built in (aka “wireless router” to connect to their modem, and then connect both their wired and wireless devices through it.

I would do this.

Connect your PC directly to that wall port, and reboot it. If it then has Internet connectivity, check what IP address it is assigned (How you do that depends on what operating system you’re using - google it)

Once you’ve got its IP address, you want to see if it is a public/routable IP address, or a private/nonroutable one.

If its a public one, then you almost certainly only get ONE IP address from the connection, and cannot connect multiple devices without a home router (which do NAT to allow the one IP to be shared)

If it is a private one then you have some other issue. Note that once you install a router, then devices connected to its LAN will have private IP addresses, rather than the public one that will now be assigned to the router’s WAN interface.

Private nonroutable IP addresses include any that start with:

192.168.*

10.*

172.16.* through 172.31.*

https://datatracker.ietf.org/doc/html/rfc1918#:~:text=1996%0A%0A%0A3.-,Private%20Address%20Space,-The%20Internet%20Assigned

as well as

100.64.* through 100.127.*

https://datatracker.ietf.org/doc/html/rfc6598#:~:text=Address%20Space.%0A%0A%20%20%20The-,Shared%20Address%20Space,-address%20range%20is

It would only work if the ISP router also supports aggregation in a way compatible with the switch (and you have access to configure the ports for it)

However, the point of greater-than-gigabit service is primarily to allow multiple devices to share the high speed. There are very few common situations where one individual device is going to be able to use that much at once.

Safe from what? Safe FOR what?

Unless both the router and rhw switches support link aggregation, and you configure it properly on both, each switch should connect using only one cable.

You could connect other devices into either of the spare ports on the router, if convenient. Maybe a home server or something?

Fwiw, the 4 ports on your router are part of a switch too, just one that is built in. And there is at least.one additional logical port, that connects from that built in switch to the router part internally.

I don’t think “give away” would be the right concept. More like “included with service”

NO ISP modem connects to the ISP over Ethernet.

The only advice I offer is to hire a licensed electrician before you electrocute yourself and/or set your home on fire.