If I may propose something. When talking to other users, the Adalo learning curve is very different individually, so if Adalo wants to show all app potential, one has to have a paid plan, as the price whether monthly or yearly is a bit high for those who are learning or developing yet. This becomes a blockage for many potential users.
May I suggest 3 options:
You can create a plan Sandbox that would only allow users to develop but not publish, so Academy type, for a price of whatever.
A more generic approach from other companies, pay a small fee per month until you have your first app published.
I would prefer to pay 5/10€ /Month for the free plan but with access to API than to have free plan and not being able to use it.
This would also allow Adalo fans to develop/learn at their own pace but also assure passive income on a monthly basis.
In my opinion this would only create less frustration and increase conversion rate.