Typically when people say "You're the x of all of these problems", the x is typically "root"

root

You're the root of all of these problems.

the source or origin of a thing: The love of money is the root of all evil. (definition 7)

Typically when people say "You're the x of all of these problems", the x is typically "root"

root

You're the root of all of these problems.

the source or origin of a thing: The love of money is the root of all evil. (definition 7)

Alternatively, you could be referring to "origin","source", or "mastermind"