over the top
excessive, dramatic behavior
way too much

From STEM, an abbreviation short for "Science, Technology, Engineering and Mathematics", a STEMlord is a pejorative term for a particular kind of person who has studied in these areas at university or works in these fields who holds a pretentious, condescending attitude to anyone who has studied in any other fields, particularly the Arts and Humanities. They typically believe themselves to be more "intelligent" and "rational", while generally remaining incredibly ignorant outside of their areas of expertise and having the charisma of a rotting pig's backside.

Doing the absolute damn most. For no reason.

Someone who is over the top for completely unnecessary reasons. They will go out of their way to prove this.

Over the top
Always doing the most
Excessive, dramatic behavior

when you have to be better and overly go up and beyond for unnecessary reasons.