Thank you so much for your answer.
You are correct, ScrollSmoother does leverage native scroll. I found a table on the lenis page that resume strength and weakness of all library
Even if ScrollSmoother, with it's approach can smooth everything, to me, the cost for this is too much high. You lose some essential accessibility features like ctrl + f as you mentionned, you lose css sticky, you lose intersectionObserver, the library is 10x bigger...
The only thing that miss me is the build-in animation system. I can, for sure, manually add elements with ScrollTrigger with some javascript, and I will, but it's definitely comfortable to be able to add some cool parallax effect with just some data-attributes.
I wonder if the built-in animation system of ScrollSmoother could be externalized to a standalone plugin with the compatibility with ScrollSmoother AND native scroll. It would make sense because, after all, animation system and smooth scroll are 2 different things.