I've implemented both x86 emulation and CSS layout.
Assembly is fundamentally simple, but difficult to master.
CSS is fundamentally insane, and impossible to master.
A lot of people think Casey is joking about CSS being harder than ASM. No, it's actually unironically true. Web spec is way more complex than any mainstream ISA you might ever need.
If you've mastered the dark corners of flexbox and grid, if you know subtle differences in how browser engines treat font sizes, if you ever worked on reducing CLS and optimizing LCP - x86 assembly will be a piece of cake for you as soon as you learn a little bit of bit math.
I swear to you, mental overhead of being closer to the hardware is orders of magnitude lower!