I like what Material for Mkdocs did as well. They ship features to sponsors first and release for free when a certain founding goal is met:
https://squidfunk.github.io/mkdocs-material/insiders/
Roughly 10xed their sponsorship revenue in ~1 year.
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...