Stop trying to teach them to distinguish "bad" and "good" links. Instead, focus on ensuring their computer cannot be compromised by visiting a website and phished credentials are time-limited or otherwise useless to the attacker.
You can get _some_ users to use a password manager, but you can't enforce good passwords and practices. The only real solution is multi-factor auth, preferably via FIDO U2F and/or biometrics.
Providing libraries to hook into your key management service is good, but the only solution is to implement identity-based, short-lived, automatically procured access credentials instead of static tokens.
There is no prevention, only mitigation and detection. The cost for this increases proportionally to how likely you are to be targeted here.
Accept it, but try to at least limit the number of places on your network from where they are pulling them in, so you can add _some_ monitoring, alerting, and vuln checking at the choke point.
This is wny you need multiple levels: layer 7 auth and layer 3 automated, identity-based microsegmentation.
That's chasing your own tail, mostly futile busy work. It seems important (and makes you seem important!), but perhaps instead aim for regular, automated, unattended software updates.
Even DoH and DoT cannot address that. DNSSEC is not going to come and save us. Somehow even #infosec isn't really fighting this. #ItIsWhatItIs