[athaca]

(serious) how do I become a kernel engineer coming from a background of javascript and swift?

[saagarjha]

Learn C and how operating systems work.

[ajxs]

There are a few basic tutorials here: https://wiki.osdev.org/Expanded_Main_Page that can definitely give you some insight into how kernel development works. It's an incredibly disciplined and broad field, but very interesting too.