The English is a more advanced opening system and probably to complex for most beginners to learn
If Magnus plays c4, why do most beginers not?

He also played early g5 and other strange things. Dont copy all of his openings only because he is the best He just varies to avoid getting bored.
But nonetheless. c4 is a solid and good opening

1.c4 is like a sicillian that doesn't put you behind in development, but it's awkward to try to build the large centre with the same motifs when you aren't explicitly ahead either. It is a move where you can guarantee a central edge, and it might be the best starting move on the board at a very high depth but it isn't necessarily clear in the sense that finding all the best moves early on in a 1.d4 opening is. It also often leads to closed positions, where your "leg up" isn't necessarily as valuable, , because black has more time to sort things. IT requires you to play accurate chess for an extended series of moves.
As someone who plays with 60% accuracy, I think my rating would be 200 points lower.... haha.

c4 is defending one of the centre squares but don't play it sometimes you could get confused and it blocks you bishop you can play it if you want

*Everybody here*: No you can't play c4, it's too advanced, you must know a lot of theory.
*Me*: Hahaha c pawn go forward.
Why can't we play c4?