As a new player if you play something off meta or weak how likely are you to be able to raid?

I come from FF XIV where I have 35k hours where all the classes are decently balanced but finally hit burn out and wanted to try WoW, however I was wondering how many people live and die by being meta slaves and will deny any off meta classes.

Atm I am lvling a frost DK and loving the reactive proc based combat compared to XIV's static rotations where I can literally open up a yt vid on my 2nd monitor and still parse high, but I have also seen multiple vids that Frost DK is not doing well in endgame. If I continue playing Frost DK how likely will I actually be able to touch the endgame raids and what not compared to playing something like unholy that is meta atm?