I am a simpleton when it comes to this technology and have just one quick question please... have I bought the wrong router?

I bought my router purely to connect my freesat box to the internet using a vpn.. so the router will be directly connected to the freesat and wirelessly to the internet.  I thought it was going to be easy and have sat down to read the specs and have just read that in order to use smart dns I need open vpn client.. but this router doesnt . it has vpn pass through... but it does have l2tp.. now i'm lost.  I haven't even started to set it up because of this quandry..Does this mean that I ve bought the wrong one?

A last question is can this router be flashed with dd-wrt?.. the only routers I can find on the list are C5 ac1200s.. mine is a C50 ac1200 ?

Any advice much appreciated.. in a former life I used to build computers ha ha!!!