Question DSL internet connection

Jul 12, 2019
Sorry if this is the wrong spot or the question has been asked before, please redirect me then.
I recently moved from Romania to Germany and the internet connection here is via DSL, which I'm not used to.
My contract is with Telekom, the one for the 175Mb/s line.
To use this I need to get a special router with integrated modem (Fritzbox starting from a certain model) or one from them, the Speedport Smart 3. The landline phone would be connected to the router. I was told the router/modem should support super-vectoring.
As I had a Wi-Fi Router (both a TPLink TL-WR841ND and a TL-WR1043ND), I figured I could get a DSL modem and use my own router. In the local store I only found a D-Link ADSL2+ DSL-321B modem.
Should this solution work? I tried configuring the modem and accessing the web (the PC was connected via ethernet cable to the modem) and couldn't. What would I need to change? The modem isn't a fit, or is it just not good enough? Do I need a splitter between the phone socket and the modem (I am not planning to using a phone)? Or did I just mess something while setting up the modem?
DSL is not just one thing there are many variations. I have not seen one that will go 175mbps but they may have fiber very close and use dsl for just the last part. You likely need a VDSL modem but this is something you will need to research on the ISP web page or call them. VDSL tends to be tricky to setup if they do not document all the setting well.

Best bet is to buy one of the devices they say will work on their system. If you just want better wifi coverage just disable the wifi radios and use your other routers as AP. You can also just put in a second router behind there if you can live with the double NAT issue. Mostly it is game console that have issues.

If you really want to not have their router most modem/routers have bridge mode. The second router likely will need to run pppoe on the wan port and you may need a userid/password. In most cases there is little issue letting the modem/router be your main router.