So, I’ve done some additional testing, and running Dashboard Kanji Sorting, Open Framework and ganbarometer-svelte worked just fine.
Right after installing either ganbarometer-svelte or Dashboard Kanji Sorting, sometimes, one of the two would not immediately appear, but it was just a matter of refreshing and they both worked flawlessly at the same time.
Since I can’t really investigate it further without a specific error message or something similar, I’m afraid other than trying to refresh the website, there aren’t other things i could recommend.
Edit: I’ve updated the script (now v0.3) to run at document-end, and it seems to work every single time now.