Sounds like someone had a bad case of framework chasing and hype driven development. I support the original poster as developing your own is always better than reusing, no exceptions.

I've worked on codebases like your's before, where in-house 'we can do it better' reigned. In my experience it never was better, and when the grand wizard holding it all together got hit by a bus, everyone was blocked.

Frameworks are a common understanding that people can plug and play into. And yes, that's a critical part of maintainable code, the ability for a person to quickly get up to speed and fix things.

Do you work alone though? Do all people in your team agree with your technical decisions? If you left the team, would someone be able to maintain and improve your hand-rolled framework?

This from someone who can’t comprehend why government mandated hard hat safety standards might be good. It all fits.