I had a similar experience where someone that had prior experience with django while we were using sqlalchemy started to design a django-like ORM on top of sqlalchemy. Of course it took him some time to get working, was a hell to understand and extend and most importantly lacked support for basic features.

Fortunately it was limited to a small isolated service but I can imagine the damage on the long term if you continue that route on what becomes a huge monolith after a few years.