As a free user, I also want to experience as much as what premium users are experiencing, and with that, maybe you could make the total assets size a little bit higher 'cause I think a 5MB limit is to small since I am building an app which uses lots of pictures and graphics.
Also, for the number and extension, maybe you could make it to 15 or even 20 as the maximum for free users.
We were introduced first to MIT App Inventor which is pretty similar to this one, but as soon as I’ve heard and seen that I could do so much more than App Inventor could do, I immediately switched to Kodular (that was when Kodular was ultimately free to use).
That’s all for my suggestion. And thank you for creating such beautiful app that let’s us users to build an an app with no-code experience.