The GNSS receiver on my Bangle.js 2 was able to get a fix fairly quickly. However it only finds 5-8 satellites at a time (I've occasionally had up to 10, briefly). Looking at the output NMEA sentences:
It's found 10 GPS satellites ($GPGSV) but only 6 are used for the fix ($GNGSA; sats 01,07,08,17,21,30). It doesn't look like it's even trying to find GLONASS satellites; there's a line for Beidou ($BDGSV) but no satellites are listed. Galileo satellites are also missing. uBlox receivers allow the choice of frequencies; the inexpensive ones allow the choice of two (e.g. GPS and GLONASS or GPS and Beidou). There must be a way to turn on at least the GLONASS frequency.
The last line worries me a bit:
From the datasheet Gordon linked in, the choices are:
示例 $GPTXT,01,01,01,ANTENNA OPEN*25
This implies that part of our problem is that the antenna is not connected, or that there is no antenna (open circuit). If anyone has done a teardown of the production units, this could be verified.