This is something I probably never would have learned if not for Cross-Progression still counting all the Featured Contracts I did on PS5 as completed on Steam, but Steam has an extra Featured Contract!
The A Day at The Races contract is located near the end of the FCs menu between The Green Butcher and Icarus on Steam…
…but it’s not present on PS5:
From its description, it seems like it was a special contract made for a speedrun competition to win a custom Hitman 2 Gaming PC from March 14 to March 24 2019 (just a bit late for me to enter). So that’s probably why it only shows up on PC. Anyway, with it done now I’ve truly completed all the FCs!