Selling a course (What platforms?)

Hello, I will be selling my own course in the future.
I'm trying to decide which platform to use. When I go into some competitor's courses, I see that their landing page is made with ClickFunnels, the payment with Copecart, and the Course login page from Kajabi. Isn't it possible to go with just one? I don't want to pay a subscription for all of them. Can anyone help me with that?