at least in Germany almost all printing services do not process embedded ICC-profiles. They just assume, everything is in sRGB. So if you render the output to sRGB colour space you are on the safe side.
To my experience, in order to understand colour management it is mandatory to study not only one but several books – at least in part. A good starting place is “Real world color management” by Bruce Fraser, Chris Murphy and Fred Bunting (2nd edition 2005). Somewhat old but still very helpful to understand the basic principles. Unfortunately it is out of print but you can buy used copies at Amazon.
Hermann-Josef