>>11516029soundAnon here.
My process usually starts by setting up OBS to screen cap Kronii's stream and use "start replay buffer" function so that I can save "clips" when something happens live and so that I wont have to go through the whole VOD for the second time later on.
If I happen to not be able to watch her streams live, I would DL her VOD using ytarchive or youtube-dl.
as for trimming video, you can use ffmpeg or any other video editor. Since your planning on compiling kronii's gwak i guess the latter is better for you.
if you're planning to post your work on the thread as a sound post. you can convert your video output by using ffmpeg. ffmpeg has a lot of conversion tools that allows you to post a webm soundpost on the thread.
if you got any more question let me know, i'll be happy to help.