I don't have a period, so I'm not the best person to do it, but there really needs to be a solid FOSS alternative to flo. If GNU had more women, it'd probably already exist
I did a quick review of what FOSS options are currently out there
A comparable FOSS app called Drip has been on F-Droid since forever.
https://www.my28x.com/ I recently heard a talk from this founder. It's free and local, but don't think it's OSS. They have a high ORCHA rating, but waiting to see if they keep their business model this way
I don't know how many more examples people need to see of big tech not respecting privacy... it's just becoming a farce now. Big tech tracking woman's cycles? Of course they are. (sigh) If this doesn't gross people out enough to seriously pursue alternatives, I literally don't know what will.
https://news.ycombinator.com/item?id=47934116