Jet Engine with Cwicly?

For your use case I am pretty sure there are some simple plugins available which can give you this functionality.
Choosing JetEngine, wouldn’t it be kind of overkill?
How about this one?
Not sure how you plan to setup membership functionality, but my recommendation is an external and dedicated service, which can live inside WordPress as well via some kind of integration.
Membership plugins, from my experience, are and always have been an entire mess in WordPress.
They were a solid solution in the past, but now there are far better opportunities.

There is also a chance that we will see such features natively inside Cwicly at some point. Feel free to vote.

If you don’t want to move too deep into development, I’d suggest you to stay away from Oxygen at all.