As a general statement, I have to agree with you on this. MusicBrainz Documentation - MusicBrainz is pretty sparse. I find myself quite frequently searching in forum discussions due to the documentation being insufficient. As an example of thing I’m currently encountering, it looks like conventions around digital releases are still in debate. My general feeling around MB is, that in cases where the rules are not clear and there are multiple ways to do it, people should just choose the way they prefer and we can always come back later update the entity. Personally, I prefer to get things right from the beginning to avoid unnecessary editing work later on.
My experience with TPRs is limited, but I think just using the translated track name is better as it is cleaner. Using both the original title and the translated title as you prefer can be solved by the Picard/Tagger side of things by looking up the original track title via the referenced recording and the transliteration relationship. Of course, it might be quicker for you to just add a new pseudo-release with “Original title (translated title)” tracks than to wait until Picard gets updated.