Well any switch can do a basic switch's job, but depending on speed, reliability, and feature set that you need that's where things change.
The reason I posted the link is because you seemed to be questioning needing a router and just using a switch instead, which makes no sense if you do understand networking in that article I linked. Not a jab against you, but just trying to confirm what you do know vs. what you're saying in this thread.
Now you had mentioned earlier that if you could just use it like this: Modem > Switch > AP's
And frankly that tells me you don't necessarily understand the importance of having a router in and managing your network, and I want to make sure that it is very clear why you need and should have a good one. This shouldn't be a question, it should be known. And if I can help educate you to know this, I sure as hell well make it happen!
Understanding how a basically router works, for a firewall and gateway, it gets the 1 IP address from your ISP. That is your WAN, Wide Area Network address...your one address from the ISP. This is your access or gateway to the Internet through the ISP's network. Unless you're a business owner or have a complex home lab setup, odds are you only have and pay for one IP address and not a block of addresses.
Then the router creates and hosts a LAN, or Local Area Network. Uses DHCP, Dynamic Host Control Protocol to send out IP addresses so that devices can access your LAN and thus the Internet. The router performs NAT, or Network Address Translation, because they have a LAN address but not a WAN address.
So there is a mask request where packets are flagged for each LAN address so that you can have sessions for things like streaming, email, Internet, VoIP, etc. for each device in your LAN. This is a critical part when on IPv4 since all the public IPv4 addresses have been used up...there's merely not enough for each of your home devices to have its own WAN IP address and you wouldn't want that unless each device had a good quality firewall filtering system in-place...it'd be akin to leaving all your doors and windows on your house open, Main St. pulling up to your front door, and all your cars and private things open and unlocked. Anyone could walk in, dig in or take whenever they wanted without any effort aside from knowing your address(es). No bueno.
I won't go into how various firewall systems work, port forward, etc... I am sure you can look those up or already have a grasp on them..but I want to ensure after the last page and a half of conversation taking a different leg from where I thought it was going, I was concerned that I'm over-assuming your knowledge of network devices and again just want to make sure that you understand how a router works and why you require one on your network so it's not a question of if you should get one, but which one should you get and why (which has been explained several times in this thread by me already
).
Ultimately, I just want to make sure you have a handle on that concept so that you know how important having a router is to a network, in your case a home network. Each device I've mentioned can serve a purpose in the overall goal of your home network, it's quality, stability, security and reliability. Helping educate you to make an informed decision so you're not looking at $20 D-Links thinking they're comparable to a $80 Edgerouter Lite3 or $150 Asus, but knowing what to look for and get into so that you're doing a better investment into your home network for something that will last and keep you and your devices going for years to come.