What are already existing alternatives?

Messenger and Google Maps propose limited alternatives:

1. Messenger doesn't work when viewing an Android phone (using Messenger app) from Firefox web-browser on Linux.
2. The solution proposed by Messenger is time limited (60 minutes).
3. Both alternatives don't propose advanced privacy but secure properties such as threshold access.
4. Share with a GAFAM personal information (even they could use local encryption etc)
5. Some closed-source alternatives designed by GAFAM don't cooperate (at least at the beginning) with justice such as the Jubillar affair's one. Note that I don't know the details but he might not be using a specific service to be tracked by someone but just Google was using massive surveillance I guess.

Facebook/Messenger on desktop (same features for a conversation different than the one with only myself):

Messenger website on phone (/e/ OS web-browser):

English screens would be welcome.

Google Maps (from web-browser on computer):

When our systems indicate you may be under 18, you can no longer share your location for more than 24 hours.

https://support.google.com/maps/answer/7326816?hl=en
https://support.google.com/families/answer/7103413?hl=en
https://support.google.com/accounts/answer/3467281?hl=en

https://myaccount.google.com/locationsharing

As the Messenger alternative should provide more screenshots of Google Maps solution to better understand what they propose.