Questions on GPS tracking and Oxygen measure accuracy

Hello,

Currently I have VivoActive HR. I am pretty happy with it. The only complaint is it can only display English in Notification.

BUT, I think I need something like Vivoactive 4. I am not interested in Wireless pay.

I have three questions:

1. I saw other brands device can show your track on MAP. Does Garmin VIvoactive 4 has similar app to do this?

2. I am interested in Oxygen monitor. How accurate is it? or How consistent is it? I mean my oxygen may sometime high and sometime low, I don't need it show me accurate number but I am okay as long as it can tell me the change, like it can show 90 when oxygen is really 95, it should show 85 when the oxygen is 90. 

3. can I load map into it?

thanks