And sure, you can encrypt at rest, and perhaps even enforce that only re-encrypted versions are ever seen by the management/API web server. But fundamentally this display requirement means that if your management/API web server is compromised, users' secrets can be obtained by a process of impersonation.
If anything, AI makes running linux boxes much easier than 4 years ago; it's now faster and the learning cliff is gone to get the correct CLI commands and digging into system logs.
As you build something bigger and bigger, quickly, with several people building, guarding all the doors becomes exceptionally difficult without a kind of aggressive discipline which is contrary to the "go fast" culture.
Cybersecurity in practice until now, for most companies, has been an insurance problem, not a quality problem.
Such companies are quickly discovering that insurance is a post-hoc partial correction and not a proper solution.
This situation will not improve anytime soon for most companies.
The solution does not require any new magical tools.