It is hard to make a repairable phone that is water-proof. It’s worth reading the FAQ about this question: Frequently Asked Questions · Wiki · Librem5 / Librem 5 Community Wiki · GitLab
The Librem 5 uses the STmicroelectronics Teseo-LIV3F, which supports GPS/Galileo/GLONASS/BeiDou/QZSS, but no A-GPS. At this point, it looks like the Librem 5 will use gps-share. gps-share hasn’t tested GLONASS and Galileo, but has added some code to try to support for them.
At this point, the Librem 5 is still working on GPS support. You can follow its development here: