Remco is the rider with the highest competitive advantage of any rider in the peleton. His engine and aero combined give him Ganna-like TT speed on the flats with only 70% of Ganna's weight. Add to that, that is aero and small frame reduce the effect of slipstreaming in his wheel and you understand why Bardet, De Gendt, Campenaerts, Valverde and many others say Remco surprises everyone beyond anything they have seen from the other of the "Big 6".
This advantage has given him the ability to ridicule the whole junior peleton and win on average 10 races in his first 5 years as a pro including a semi-recovery year. He won 15 times solo, 12 TT's and 11 stage races. Wins include 10 one-day races and 9 mountain top finishes. He got 5 of the 6 WC/EC/NC championship jerseys. His win rate ~19% (including all stages where he didn't intend to go for a win), only surpassed in the current era by Pogacar's ~21% who is a year older. He has won 42% of all stage races he entered, 34% of all one-day-races (!) and 33% of all TT's. So he definitely is a hell of a one-trick pony!
Remco was initially a rider that couldn't descend, had barely technical skills, couldn't sprint and had (and still has) issues when it comes to tempo changes and optimal recovery. This is no big surprise knowing his background. These are all things that can be exploited in the pro peleton. In his case it was almost career ending when he made that mistake and fell of a bridge. However, it's no surprise that he can make big progress here and he does so. This broadens his "tricks". I would not be surprised that if he has a very long career without big injuries, his number of wins will be huge, maybe top 3 of all time. Regarding GT wins, I am not that sure. There a few riders with more tricks when it comes to performing well in the mountains and the team plays a big role too. So maybe he wins only a few of them but I don't doubt he will be a huge challenger for them, in particular in the GT's with a less mountain-focussed roadmap.