I don't know how to find the correct modem.

I hope this is a good place to ask this question.

I am a student, who is looking to set up a network in my home. I would like to replace the Century Link router/modem/switch combo that I currently have.

The internet that I am paying for is fiber-optic from Century Link, however, from what I can tell, the line that plugs into the current router is a DSL line. So my assumption is that the fiber-optic ends at the street, and then switches to a DSL line running up to the house. Is this probably a correct assumption?

I have already purchased a stand alone router and switch that I plan on using, from ubiquity. I need to find a modem to take the DSL line from Century Link and convert to Ethernet to plug into the router.

My main question is what do I need to look for in a stand alone modem? I would like one that has the most up to date hardware that I can get. I have shopped around and I see a lot of modem/router/wifi combos. But since I plan on doing routing and wifi separately, these don't seem to fit into my network right.

From what I can see, DOCSIS 3.1 is the fastest I can get. Is this correct and is there any other things I need to be aware of?

I appreciate any help. Thanks.