Would a Unity/Unreal engine style model work?
For obtaining revenue and building a community their model works well. Just not an open source community.
Unity is free for people and companies to use if their revenue is <$100k/year, so lots of people use it for personal projects and as early stage businesses. That gets them hooked and happy to use it, and builds a community of 3rd party add-ons and assets.
For any business whose revenue then grows to > $100k/year, the business can easily afford the relatively low license fee of Unity; they won't mind. That fee goes up with increasing revenue of the business.
BTW: Sciter already works inside Unreal Engine pipeline as plugin: https://sciter.com/see-sciter-lite-unreal-engine-in-theaters...
The Unity and Unreal models aren't open source, so if you want open source as a feature, as well as revenue, you can't quite copy their models.
To get open source together with revenue, you'd need to use one of the open source business model approaches.
One of those models is "open core" where the core product is open source, and there are additional features for pay which aren't.
Another model is to use GPL or a similar copyleft license for free, and require a license fee for a more open license. Qt is a well known product that uses this (qt.io), and they also offer a revenue-based discount so that smaller businesses can pay less.