Demon1 is definitely not a bad player, but he is a bit like yay in the sense that his agent pool is quite niche and requires a full system built around it. Potter was basically a system-based coach with how she swapped Jawgemo and Demon1's duelist maps depending on if Raze or Jett was the meta pick. Both players were fairly capable of playing smokes as well with both being able to play Astra comfortably. Demon1's ideal agent pool to play would basically be Jett/Brim/Astra which is somewhat feasible for almost all the maps. Teams definitely wanted to adopt a lot of the new Yoru meta and Neon meta comps, but Demon1 is not particularly a movement heavy player and, whilst I think he could learn Yoru, Demon1 seems to be more of a lurker archetype.
Demon1's peak was absolutely one of the shortest. S1mon might be shorter just because he joined right before Champs and got his trophy. Demon1's definitely the shortest peak for an MVP-esque player. He could look at EG or G2 for a more systematic team, but it would be very tricky to swap around who plays what.