Why do cities at high altitude regions have high atmospheric pressures?
The reason for this is that the reported value is the relative pressure and not the absolute pressure. If meteorological stations reported the absolute pressure, dependent on elevation, it would been really confusing. So air pressure is always adjusted to sea level.

This is also why your home barometer has to be adjusted to show the correct pressure depending on the altitude where you are.

Here are a link to the weather close to where I live. It is at 150 m elevation,
https://www.yr.no/place/Norway/Buskerud/R%c3%b8yken/B%c3%b8dalen/hour_by_hour_detailed.html?spr=eng If you seek for Drammen you will see the green line showing the same pressure but the elevation there is close to sea level 10m or so.