Stuff is so complex nowadays that there's a ton of vectors an employee can use to eventually access almost anything on production systems. Unless you kneecap their ability to reach anything at all. Even if say you use Vault for secrets, extensive ACLs, on-demand access, there's an almost infinite amount of ways to squeeze out data in ways it hasn't been anticipated. Kuberneters, containers, etc doesn't always help, often sometimes it makes things worse.

Defending against internal threat seems like a losing battle that can only be mitigated, slowing down more than preventing an attack.