Very late comment but I managed to beat the Celeste CLassic Mod (Fuji) In 1 jump (I think you can beat it jump less but I'm just not that good at spike clips) Anyway hopefully someone will make a No Jump video for Fuji (walljumps allowed)
So actually this was impossible, I couldn’t do it. Was impossible. I literally just figured out a way to do it.
The problem with 1700 was that everything is just high enough where dash-grace jumps don’t gain enough height to finish the level, and ofc the speedrun strategy jumps by necessity.
What I noticed was that there’s a strawberry here, and a strawberry hitboxes move. Because of the position of the strawberry, you are able to pop open the box, wait for the strawberry to move to its lowest point, then intercept it. You need to fall into the strawberry, but time it so that you collect the strawberry and dash up in almost the same frame, which will give you a free extra dash. Dash up again, spike clip, and then etc
Surprisingly consistent. Uses a spike jump, but this is a victory nonetheless
Edit: You can skip the spike jump by dash-jumping instead