You are braking the TOS by downloading videos from YouTube so it’s not legal.
I believe TOS violations per-se aren't covered by the DMCA, but by the CFAA (Computer Fraud and Abuse Act) instead.
In any case, DOES the YouTube TOS actually forbid the use of alternate clients to download and view videos?
Youtube red or something I think it's called.
What's the difference in using youtube-dl to d/l copyright video or using youtube premium to d/l said copyright video.
Note: I have not used youtube res service so idk how it works