Everyone prefers more ports and having to use icebreakers costs money. But the question of ending up in the cateogory of land-locked counries if broken up - there are lots of ways you could slice it and still have sea access on at least one coast and probably on coasts outside the arctic as well. If they don't have good ports eg in the eastern side it's probably more lack of investment than access to waters.

(Though in such scenarios it would seem likely they'd still be able to agree to cargo transit through the newly estabilished neighbours)

Here's a map I found: https://www.searates.com/maritime/russia