alt Hacker News.env as we know is full of problems... BUT! check out varlock (https://varlock.dev) - it's free and open source, and we have really modernized and adapted the familiar syntax (a small DSL on top) to make it much better.
Has built-in validation, type-safety, composition via functions, loading with plugins, leak prevention, and much more.
I think the idea to use the environment is misguided in general.
The environment was only ever good for things like GOMAXPROCS where you want a single point of truth for all processes on a machine but in a containerized world even that point is moot. Where regular config in the environment just problematic it is outright dangerous for secrets.