As the "Mastering Bitcoin" book by Andreas Antonopoulos and various other contributors is a good read on Bitcoin L1 I expect the Lightning book https://github.com/lnbook/lnbook by him and peers to be an equally good read for L2. I haven't read it yet though.

If you insist on youtube I suggest you visit the channel of Rene Pickhardt https://www.youtube.com/user/RenePickhardt, a developer of lightning.