Both work. They fail differently, and that is the part worth knowing before you choose.
Cohorts produce better outcomes and better testimonials, because a deadline and a group create accountability a recording cannot. They also tie your revenue to your calendar, and a launch that underfills is a bad month you cannot recover.
Evergreen decouples revenue from your time and compounds with your content. It also has completion rates that will depress you, and support load you did not plan for because everybody is at a different point.
The pattern that tends to work: run it as a cohort two or three times until the material is right and you have real outcomes to point at, then make it evergreen. Building evergreen first means scaling something you have not yet proven teaches anybody anything.