> You learned how to build the kernel, git, the kernel style guide, signed-off-bys, checkpatch, get-maintainer and finally running git-email.

These are all pretty well documented tasks. It might not be 'one button simple' like a gitlab merge request, but I thought it was pretty easy overall. It did take some time investment on my part to learn the submission steps (about a weekend total, including the compiling and testing locally).

> Large and/or controversial changes ...

I suspect if they are large or controversial, that in itself implies the barrier to merging is going to be higher. How many new contributors (non-paid contributors especially) want to merge something controversial on the first go?

Could it be simpler? Possibly. Sometimes complex systems do require complex processes for maintenance. I'm just saying I didn't think it was especially burdensome to contribute a small change as a brand-new, completely-unassisted by another person (before sending patch) contributor.