If conservatism was monarchism and liberalism was mercantilism that is what they’d be called.

I understand why that would appear to be the case. But it’s not. Conservatism and Liberalism are political philosophies and movements. Monarchism is a system of governance. Conservatism the movement supports Monarchism the system. Liberalism the movement supports Capitalism the system. Just because they are one-to-one doesn’t mean they are identical.

it matters especially when discussing these concepts specifically together.

It does matter indeed, I agree with you, and it’s important that we understand that Liberalism cannot lead to universal liberation because it is foundationally tied to private property. Eliminating private property is an illiberal move, and it is the foundational move of communism. Moving from aristocracy to private property ends Monarchism and it is the foundational move of Liberalism. Conservatism fought against private property in favor of the old system. Liberalism fought for private property in favor of Capitalism. And Communism fights against private property in favor of universal liberation.