If Winter wins, does that mean Valgavoth would be able to leave Duskmourn?

At the end of DSK I felt the general consensus from comments here was that this was a villian we did NOT want leaving his plane.

I get the vibe that many people truely view him as a potential endgame villian.

But while the moth on ravnica was worrying, he was still trapped on Duskmourn ultimately.

But while the aesthetic of this set finally seems to be somewhat more upbeat, it does have the potential imo to end catastrophically if Valgavoth gets a hold of that spark I feel.