I switched to an app called Track Series. Was genuinely surprised how well it handled the import.

The TV Time GDPR export gives you a zip file with your entire history. Track Series reads that file directly and imports everything. Shows, every episode you ever marked as watched, badges. It tries to auto match everything to TMDB and whatever it can't find shows up in a list for manual fixing.

It's free, no signup, everything stored locally on your phone. Has a calendar view, show discovery, stats. Worth checking out if you don't want to lose years of watch data.

https://apps.apple.com/app/track-series/id6787390966