Impedance matching confusion
I think your confusion is shared by many after they first encounter the maximum power transfer theorem.  In essence, many forget the question the theorem answers.

The question the theorem answers is:  For a given source impedance, what load impedance results in maximum power transfer from source to load.

Unfortunately, I've seen trained engineers reverse the question and then try to apply the same theorem, i.e.:  For a given load impedance, what source impedance results in maximum power transfer from source to load

Many who should know better will answer "match the source to the load".  But that's just plain wrong.  A zero source impedance delivers maximum power to any load because there is no power loss in the zero source impedance.