@CarlMacLawrence: I really appreciate your thoughtful comment!
At root, I actually don’t care too much whether the two-parters are collapsed into a single episode or not. But I do care that Trakt matches TMDB, if they’re saying they’re going to use TMDB as the authoritative source. For those of us who use services like Plex to organize our media (which, by the way, we ripped from our DVDs, rather than watch “in syndication and on Paramount+”), we use TMDB for episode numbering and ordering.
Trakt made the decision to align with TMDB, so having one-offs creates difficulties for a non-trivial number of people.
And TMDB is notoriously inflexible when it comes to their “rules”, and they are going to follow the “prime run”, even when there’s a good argument (such as the one you offered) for splitting it into two episodes. Trying to get TMDB to fix episode numbering/ordering is like beating your head against a wall.
Al in all, I think it makes more sense to have Trakt match TMDB, however distasteful that might be in some respects, because it means wrestling with fewer one-off discrepancies between the platforms.