Hour/Date issue

setting the date/time is not saved in the nrf52832 Real Time Clock as I expected it to be.

Unfortunately the nRF52 can't keep the full time in the real-time clock when it powers off or does a hard reboot. The RTC just doesn't have enough precision.

Can we have the choice to have the date/time set by user or GPS ?

Not sure I understand what you mean? You can ALWAYS set the time up using the settings menu.

GPS time is only checked if the watch starts and the date is still set to 1970.

Somehow the date got mixed up (battery didnt ran out) and everytime I restart it takes back the old time/date.

If you set the time/date correctly from settings the clock will be fine. It's then only when you do a proper hard reboot (BTN1+BTN2) it'll be lost.

If you use the GPS enough outside to get a lock, any time from then on that you do a hard reboot the time will be grabbed from that.

However right now we don't try and set the GPS time up when the clock time is set - the only way to set GPS time is by going outside with GPS on.