Formally, “hubiera”/“hubiese” is only used within subclauses, i.e «si lo hubiera visto, habría hecho algo» etc. They never stand as the only verb and don’t appear in simple clauses. You can’t say “hubiera hecho algo”, it’s “habría hecho algo”. Here, the subjunctive (hubiera) is doing the same job as “were” in english, and the conditional (habría) is equivalent to “would”: «if I were luckier, it would have worked out». This is the case with subjunctives in general, they mostly only ever appear in subclauses other than very specific exceptions (such as negative imperative or vestigial expressions like «Dios quiera que…»). The trick is learning which subclauses use indicative and which use subjunctive :)
Informally, though, natives will tell you that it doesn’t matter because it truly doesn’t. The formula “if (subjunctive) then (subjunctive)” is understood by everybody with the same meaning as “if (subjunctive) then (conditional)”, and you can even use it in formal settings such as when talking to your boss, at least in Spain.
Source: Am native, from Spain. Good luck with the language learning!
Some time ago, I met an HR person at my job. She wasn’t actually part of the workplace HR team, rather, she was more like a classmate of mine, but she had worked as HR in the past and wanted to continue to do so in the future. She was kind and polite, so I never had any beef with her, but she consistently had the shittiest, most inhumane takes on how to manage and interact with people I had seen in a while lol.
Meeting her made me arrive at the conclusion that you just said. Empathetic people that get into HR with the idea of helping make the world a better place would eventually resign or, at least, be very ineffective as HR. The only people capable of staying in HR for a long time are sociopaths who don’t mind lying and being obtuse in job offers, and ruining someone’s life so their boss can squeeze a couple of extra cents. The profession itself only serves to make companies more ruthless and adds nothing of value to the world.