If you do want to work there, though, maybe check the legal situation first...
I am almost certain, this counts as unauthorized processing of personal information. Just because you have access doesn't mean it's fair game to do whatever you like with it. Especially archiving, keeping a history or linking (external) data is not the intended use for such an interface. If you take the information home with you, e.g. on your work laptop, that may be a whole nother can of worms. May even count as business secrets you're exfiltrating.
At least in Europe, abusing such an interface likely would be illegal, certainly if you keep a copy/diff. Your employer may have to act against you, or become liable. Or they may use this misconduct later to conveniently terminate your contract (lol, especially, if you use your insights as leverage).
I presume the larger the network, the more likely this will get you in trouble. Conversely, collecting the data has little use otherwise.
How about you organize with your colleagues to voluntarily share employment information to gain collective leverage?