I'm sorry but anything that hijacks the scrollbar in any way is just a no-go. You have to not interfere with scrolling. (Taking some other action on the page during scrolling can be okay, but actually affecting the scrolling itself in any way while you are scrolling should be verboten, in my opinion.)

Lenis.js (smooth scrolling lib) was actually implemented for some technical reason that is no longer required; so might actually remove it indeed.

Pages interfering with how scrolling works infuriates me so much that I've often considered writing an extension that tries to disable that behavior, or even compile my own Firefox if I had to.