They're completely different games, honestly. Frostpunk is completely on survival. Civilization is all about progressing into the future. With that said, CIV VI multiplayer is very fun.
I'm very tempted to play Frospunk since hearing what it like and how hard it is. Played Civ in the past and whilst I like them, they get a bit same-y for me and have to force myself not to alway play the sameway.