This guide will show you how to download entire YouTube channels. I'm going to try to keep this as simple and straightforward as possible, and I'll also try to explain some of the why's here as well so that you can better understand how to modify this guide for your own personal use.
The first thing you're going to need is yt-dlp. Once upon a time we would have used youtube-dl, however the developer there didn't seem to keen on bypassing YouTube's throttling. yt-dlp is a fork of youtube-dl that performs far better on YouTube.
How you will get yt-dlp depends on which operating system you're using.