There are four basic low-level components you need to understand.
First is the modem. This translates from the service provider's protocol to standard IP. There are a lot of different kinds of modems, depending on the service provider's protocol.
Second is the router. This takes any IP traffic from the LAN side and directs those packets that are addressed out to the WAN side (but not packets targeting LAN addresses). Often a router does network address translation, translating packets coming from the WAN addressed to a specific port to a specific LAN IP address and port. It will also often support DHCP, handing out of LAN IP addresses within a defined range.
Third is a switch/hub. In both cases these take packets from multiple computers and the router, and either broadcast to all other computers/router on the hub or send along only to the addressed computer/router on the switch.
Fourth is a wireless access point. This takes packets coming in on a single (wired or wireless) connection and broadcasts those out to listeners using one of the wireless protocols.
Now that we've exploded the whole thing, you will typically see three combinations of these:
1. Wireless Modem: Modem + Router + Switch (usually, if it has LAN wired ports) + Wireless AP
2. Wireless Router: Router + Switch (again usually) + Wireless AP
3. Wired Router: Router + Switch
But, of course, you'll see pretty much every combination of these available if you look hard enough.
Generally speaking, the cheapest option is to use a Wireless Modem, as it combines all of the components into one shell with one circuit board. However, it also puts all the proverbial eggs into one basket; if any of the components breaks down the whole thing needs to be replaced. Also, if one becomes obsolete (likely the wireless access point but also potentially the switch), it is difficult to replace just the obsolete component without replacing the whole thing.
At the same time, it is often advisable to at least separate out the Wireless Access Point, as the corner of the house where the cable comes in is rarely the best place to put the access point to reach all corners of the house.
Hope this helps.
By the way, you check of Wi-Fi Router: Huawei 5G CPE Pro, Huawei Router A2 and ZTE 5G CPE Indoor WiFi MC801.