If you like videos, there are some excellent ones by Richard Borcherds, in very different style to 3b1b but by a Field's medalist

This is his algebraic geometry playlist. The whole course is directed at graduate level but the first few videos are very accessible https://www.youtube.com/playlist?list=PL8yHsr3EFj53j51FG6wCb...

first thing i did when i read "3rd degree polynomial" was search "elliptic curve 3b1b"