are there days where you only train certain parts of your body / only do certain exercises because you simply don’t have the time for a full workout?
my ideal workout means stair climbing, running-walking and stretching. It can well last 2 hours.
Some days I don’t have enough time to do all that. Would it be better to do less of each kind of exercising or just to fixate on one kind?
Try to follow at least the WHO recommendation of 30 min of moderate exercise per day on average. Maybe you can consider this budget and balance it over your week depending on how busy you are.