Why does Windows 10 still feel smoother than Windows 11 on older hardware?

Every time I use my old Windows 10 laptop, it feels snappier than my Windows 11 machine—the Start menu opens instantly, search actually works, and File Explorer doesn't lag. Is this just because Windows 11 is heavier, or is there something specific that makes it feel so much slower?

If you've used both on the same hardware, did you notice the same thing? And is there any way to make Windows 11 feel more like Windows 10 without breaking stuff?