the initiative does not go to far into details with this, but any acceleration of trans-european railway extensions is good in my book - you may want to read this
this is okay with the rules of this community, I hope? Still pretty new here, but I am not in any way connected to this initiative, I just stumbled upon it and liked it, and thought that others might be interested as well
I’ve had a pleasant experience with rail-on-ferry when I traveled to Sicily. It probably wouldn’t work for Finland, however, as their train gauge is 1522mm rather than the common 1435mm.
Rail-to-ferry should work, however. Stockholm has very pleasant ferries to Turku and some that take a little longer to Helsinki. Both should help connect Finland.