Ask HN: Any decent open-source CGM software?

I have some experience with Nutrisense Continuous Glucose Monitors (CGM) , and the experience is very user-friendly through the app. The problem is it costs $225/mo, and most of that cost is in the software.

I think you can get Libre CGMs for $40/mo but they don't come with any software or insights.

There has to be an open source solution, right? On google I saw a few people built their own projects, but I'm wondering if anyone here is familiar with the range of open source in this area and what the best app is.