I haven't used the devtools protocol of Firefox but CDP is one of the worst protocols I had to work with. Everything is "experimental", inconsistencies between different domains, multiple ways to do some stuff and revealing internal stuff.

Seconding this, I've used CDP directly to solve problems and it's a horrible protocol with a really buggy implementation. The documentation is pretty sparse and the implementation is inconsistent with the documentation sometimes.

It's true that if you want to know what a method is named and which parameters it takes you can find that out, but I rarely found the answers I actually needed to use things correctly.

Yep, in certain cases requests/responses will only show up in the Fetch domain, sometimes only in the Network domain, and sometimes neither!