Questions about ASUS Dsl-Ac68u

To replace a provider router, do I necessarily need a router with modem function or is any other router also possible as a replacement? I'm looking for one that transmits faster and stronger than the one from the provider. In particular, it should be able to transmit Wilmaa, Zattoo and others to tablet and smartphone without interruption. Even over several corners and metres. And I know that I will lose the support of the provider if I use a device other than the provider's own router. No matter.

Is the DSL port Rj11 or RJ45???

Is it a VDSL analogue or ISDN router?