I use Trakt more and wondered if there was a way to quickly move over to Letterboxd as it seems to be the favoured platform
Importing data
Importing your data Letterboxd members can import data in one of three ways: directly to their account (as watched films and/or diary entries, with optional ratings), to a new or existing list, or to their watchlist. When importing data we support the following formats: Letterboxd import format...
letterboxd.com
Not sure how familiar you are for running scripts, but it looks like someone has written one to do so? There are import tools in Letterboxd if you can get the Trakt data in a format it accepts.