Fit accuracy on printed parts

I have an Ender 5 S1 printer. To reduce print time, i often break a design into pieces and created tabs or other fixtures to fit the parts together. I am looking for tips on how to improve the precision of the prints so they friction fit decently. Are there slicer settings that I should adjust? I find there is some variation as well on hole sizes. For example, if i size a hole for an M3 screw, sometimes it slides in nicely, other times it is undersized.

I am posting a related question in the CAD forum, in case my design specs are two tight need additional space for fit.