I recently tried my hand in commercializing my open source project, gitleaks (http://gitleaks.io). I'm keeping the core gitleaks project MIT but changed the gitleaks-action on GitHub to a commercial license. Revenue from the commercial license and maintenance agreements has netted me much more than donations I've received over the past couple years. I encourage any open source maintainer to try and find a business model (plugin, dual license, enterprise support, etc) for their project.
Maintainer of Material for MkDocs here. Correct! The Sponsorware strategy is an alternative to dual-licensing which works fairly well for our project. If you have a successful Open Source project that is a pain killer and product-market fit, this strategy might also work for your project.
FWIW, here is a blog post explaining the rationale behind starting an LLC https://blog.gitleaks.io/gitleaks-llc-announcement-d7d06a52e...