You noticed correctly that all stars do not have the same colour. However, it is rare that you'll blow out the stars because longer exposure will give a star trail. ISO has to be set appropriately. The problem with ISO is that not all cameras (with different sensors and sizes) behave similarly. Usually, a full frame will yield a cleaner picture compared to a smaller sensor.
With my D4, D5 and now with my Z6 and Z7, I can go upto ISO 3200 and still be satisfied with the picture quality, but if I am using D800 (7 years old) I'll not go above ISO 1600. Also, with my APSC D500, ISO 1600 is the limit. So you will have to tset your camera for high ISO picture quality.
Normally the setting I used for shooting wide scene astro photos are as such:
FX sensor,
f/2.8, shutter speed 25 secs. for focal length 14 to 24 mm. Interval 30 secs.
f/2, ss 15 secs for FL 14-24 mm, interval 20 secs.
f/4, ss 25 secs for FL 14-24 mm, interval 30 secs. I then increase the exposure in post and use more than normal noise reduction at the cost of loosing few stars.
Henry