IKEA crib and mattresses

Ke

We purchased an ikea crib Sundvik. And we have a Sealy mattress. The mattress is about 1.5 inches too small for the crib. After looking online, this is a common problem with ikea and mattresses. I really don’t want to purchase an ikea mattress, poor reviews and not nearly as nice as the Sealy we initially purchased. Anyone else have this issue? What mattress did you end up purchasing?