The issue here is that you are trying to bridge two disparate goals - making money and helping kids.

The fact that this isn’t open source, as it stands, means the latter is not a primary goal - which is not an indictment, just an observation.

The complaints will come, regardless, for that reason alone, given the marketing/narrative.

You’re selling a product to parents/educators who want to gamify the technical education of their children. That market, small as it is, despises micro transactions.