And all these years I was told security through obscurity wasn't a thing...

I work on desktop applications. Tech stack is visible to anyone who can see the error message.

If you got a web-based SaaS sure I understand your position, but then you spit all that good stuff into a log and have the error message include the relevant log ids so support can easily find it. If something bad happens while loading a file, include the filename in the logs, and so on.