Accents don't seem to matter
Since I started the course I've been consistently to use the correct accents wherever needed. Recently I discovered that it actually doesn't matter. You can put it, not put it or use a different one entirely. I hope this isn't intentional. It shouldn't necessarily be counted as wrong, however it should at least give you a typo warning.
Thank you for all your hard work for the course!
It should be counted as wrong because it is. Those aren't accents but totally different letters. An Ä is not an accented A but something different, same for Å, similar for Ö/O.
The course is in beta. It probably will be possible to enter these letters via a virtual keyboard later, when it graduates. Hopefully a wrong letter will be a hard mistake, because that it is. An accent is mostly a hint, still obligatory, but not exactly changing the meaning of a word, so probably not a hard mistake (debatable, maybe this could be a setting or get obligatory after some time or amount of mistakes).
Different ladders change the meaning of a word.