https://en.wikipedia.org/wiki/Powergaming
Powergaming (or power gaming) is a style of interacting with games or game-like systems, particularly video games, boardgames, and role-playing games, with the aim of maximising progress towards a specific goal. Other players may consider this disruptive when done to the exclusion of all other considerations, such as storytelling, atmosphere and camaraderie.
Minimizing effort to maximum something you want or your chances of getting it/doing it.
Making mechs takes a reasonable amount of effort and time, and your motivations to do so might be as benign as just wanting to learn the job.
Space exploring takes an amount of time, effort, and luck as well. But probably, if somebody has a habit of finding space loot and stirring the pot when they bring it back to the station they should be told to knock it off.
Is cargo ordering guns for no good reason except "we got money" powergame?
Non-antag guncargo is stupid and leads to the same unfun mess most of the time it happens, whether it fits the powergaming rule or not, I think a sane person would agree it should be a rare thing, not an every other shift thing.
Is xenobio making a sepia extract and holding onto it the entire round "just in case" powergame? (Science might just be powergame-the department) Is a scientist making a spin inverter, sticky taping it, and keeping it "just in case" powergame? (This results in whoever is stuck to it teleporting to the other spin inverter)
Again, like robotics, this is at least an example of an actual job on the station that requires time and effort and planning. There are probably some items that players in engineering and science should be expected not to rush and hoard every single round (like your spin inverter example), but in my mind, these are better more common examples of powergaming that have an impact on the atmosphere and quality of RP in rounds:
Non-antags incessantly hacking into places and nabbing things they supposedly
"""need""", instead of asking for them, finding alternatives, or just doing without.
Making improvised weapons for no reason.
Begging for access not included in your job every single shift, be it extensive access you have no RP reason to need or limited access solely to avail yourself to your favorite gamergear.
Security (Warden and HoS excepted) lugging around lethals ASAP for no reason.
The above are things that are to me against the spirit of fun and RPing as being an employee on a space station. They degrade actual good RP that comes in the form of cross department communication and cooperation, chain of command, fairness, and focusing on your job rather than preparing for eventual le epic click battle.
Early on when Manuel was new it wasn't crazy uncommon to walk into tool storage mid round and see a pair of insuls still just sitting there, and when I saw them, I'd think "eh, I really have no more reason to take those than did everyone else who left them alone."
I'd, in a heartbeat, trade the entirety of what Manuel has become to go back to that kind of atmosphere. Not going to happen, but oh well.