I used to share a similar sentiment about speed, especially after having burned out hard around 30. But after recovering, I think I may have overcorrected. Momentum is very powerful, and it's hard to gain momentum at low speed.
Speed is important but going fast doesn't mean going as fast as possible. It's about going fast sustainably. Work speed isn't binary. You can be fast without being the fastest.
The speed that's between "slow" and "fast" is called normal, and far too many companies, people and leaders deeply believe normal counts as slow.