What do you need to learn from web programming to do this?

Question

YouTube

Previously, YouTube had the ability to sort channels into folders. Now removed. (channels about sports in a folder called sports, etc.)
I know about add-ons for browsers that "restore" this feature (but this is unreliable and inconvenient)
I went into my subscriptions (I am subscribed to 1200 channels) And it would be fine if I watched entertainment content. .. but no.
And I thought about creating a convenient channel manager (separate from the program browser) - you don’t even need viewing there, just convenient sorting (well, it’s possible to inform who and what deleted ... otherwise you go to the video playlist, and some items are written there " video deleted" - what video?! I came here a month ago! With what name, from what channel?)
What technologies to study? (I had no business with the web) - I only know JS and WEBGL.
As I understand it, I need site parsing and, accordingly, the task is this.
Collect the following information from YouTube:
All channels I subscribe to.
Channel names, what videos and playlists are on the channel (number, titles, previews, links), etc.
Please guide me on the right path.