Here is a similar Thin-Crust Open Core model https://reactflow.dev/blog/asking-for-money-for-open-source/. But I hear CH and understand their move. I think OSS Sponsorship has failed; it does not generate enough money to pay a team of top engineers. The best move would have been to implement better paid support model and allow more users to pay for support. Currently CH charges immense amount for their support, so only large corporations could afford.