Paralino is based in Germany. It's an end-to-end encrypted geolocation sharing app that is quite new. They said they will open source their code further in their roadmap. It's available on both iOS and Android!
Matrix allows for time-based location sharing. The Element clients have it implemented.
Also Nextcloud with the Phonetrack application installed. I use the uLogger app on Android for 24x7 location recording and it uses less than 2% of the battery over a day.
I too was trying to find alternatives to these services but I could not.
I saw a github "thread" ones for organic maps, but it did not get traction... They could make it a paid service as that are trusted by the community to handle that data.
There was a new application, I do not remember the name of it... But it was using google play services which I did not add to my OS.
I found the app through howtomen's YouTube channel, let me know if you need it, I will search for it.
Edit:
If you have the skills, you could setup/self-host owntracks, which I could not do, securely.