PhD student wanting to do "the minimum required"
There should be some university rules which state what the student has to do in order to obtain the phd. Treat them as a contract -- do they state exactly some minimum requirements to obtain the phd? Then, a student satisfying thoss requirements should obtain the phd. If (what is more likely) they say something about you being able to state more requirements, then you can give more requirements (maybe after writing them down formally). (Or maybe the rules allow you to remove the student? If yes, you might want to think if you want and can do this.)

Please be also aware that you may be requesting too much.  Some instructors were always the best in research and may be biased when supervising.

If the student meets the minimum requirements, they should of course be granted the phd. Not doing more might or might not be a problem for the student's future. You should warn them that (e.g.) an academic career might be a problem afterwards, but, depending on the student's goals, receiving a "minimum phd" might be not at all a problem.

Many people in the world do only the minimum required for their job/studies. If the mimimum is defined well, this should not be a problem.