Don't know if people will see this and I'm not an admin or anything, just here too often and wanted to put this somewhere slightly visible, but:
If you see a credited translation, please do not remove the credits without permission from the translator.
If part of the translation seems incorrect or unclear to you, it is my opinion that you can modify it, as the benefit of having content on a fandom wiki is that things like that can be crowdsourced. I've done my fair share of modifying official and fan translations on here (and I feel terrible about it every time because it feels like undermining others' work) but I only do it for the sake of putting accurate content on the wiki.
If you are only modifying the wording of a phrase or changing a few lines and not completely uprooting the original credited translation please do not remove credits - I feel that adding "based on" or "modified by x" is good to both give credit to the original translation and acknowledge that it is different from their original translation (so people can look for the og translation and decide which one they agree with more, if they wanted to do so). I understand that if you're modifying a translation there will be lots of places that you'd translate the same way as another person but it's just polite to acknowledge the work someone else has done even if part of it needs to be changed.
Also, in general it's good to have an account on fandom instead of editing with your ip so that other people can contact you about the edits you make if they wanted to, and also to leave a credit for your own translations so people know where the information is coming from.
Thanks, and let's make the wiki a great place for everyone :)