Well it isn't fun for the possibility of not receiving any votes in spite of rating other entries because a thought in my mind is we'll be buried if other teams don't figure out how to vote on other entries 🙃
the karma system on itch is also designed for the purpose of allowing every entry to get its fair share of attention while also letting other teams know that voting on other teams is a good thing and will increase their karma.
Sorting by score at the end already declares winners - having the highest score in your respective language bracket is already a "win", because it is a way to rate the entries. Such a rating system is already a quantifiable way to measure "quality" - even if it necessarily doesn't actually dictate as such.
I agree that voting on other entries is fun. But I fully disagree the voting system as a whole is fun because I have to deal with anxiety if my entry will be voted on at all (which ISN'T FUN!!!), and I only have to rely on my language bracket to be able to do so, and they must play the same game they already know start to finish to be able to even rate, and it ends up in a large mess where I wish it was about the substance of the comments and reviews instead and not about voting so I could at least send it to my friends and family to leave a good word and not bother with the fact that their opinion is "lesser" because they're forbidden from voting.
The karma system is specifically designed for this issue and I'm curious on your reasons why you're not using it.
I also want to be blunt that these are all choices you made for this contest. These are systems that encourage specific behaviors and our entire team is actually depressed because of the way the winner situation was handled, the lack of communication on the scoring system, no tutorial on how to do it, and the fact that contributors CANNOT VOTE (despite being stated elsewhere that they should, I'm the only one in our 8 person team who can even rate entries).
I think the 2 week period to judge other entries is a good idea. But the voting system itself is inherently competitive and runs against the core of the contest you stated. It really sours the mood and if the score system was removed, replaced with "judge other entries, leave a comment, entries will be sorted by karma during the judging period" means that the process of judging and reviewing entries would've been the encouraged behaviour instead, rather than scoring a randomized list of entries.
Despite this I'm still thankful for this jam, it was extremely fun to participate in when I didn't have to think about the score system or anything related and I had more fun commenting and reviewing other entries that I could understand in my own language :)