I installed the profile for macOS Big Sur, but I got updated to Catalina beta 10.15.6 beta instead. Is it possible to install the Big Sur beta already?

I'm going through the docs on subscriptions and free trials, and it looks like free trial are only for renewable subscriptions. I'd be interested in a free trial that does not roll automatically into a renewable subscription but that requires the user to explicitly opt in to a subscription tier once the free trial expires. Appreciating any pointers in this regard.