TDU and Olympics dont really matter here.He wants it all so... Is it meaningful that I finished Assassin's Creed Origins at 100% when it wasn't even fun to do. No, but sometimes we just want to finish the list and check it all off.
He only needs:
* Vuelta
* Tour de Romandie
* Tour de Suisse
* Basque
* Tour Down Under
* Roubaix
* Olympic Gold.
Those first 3 he might do this year, then he can easily do the next 2 in 2027. Roubaix he can try every year until he stops, he'll eventually get it. Olympic Gold might be the hardest because there's only 1 chance left. Would be surprised if he still races in 2032, and no one is better.

