Did I do the right thing turning down a 40% hike offer

So I recently gave an interview to a company, cracked it and got offered 50% hike but I was very hesitant joining there because they said they'll demote my role to a Jr Engineer, because they said my code wasn't as good as they wanted.

The task was to add a new feature in their codebase, all I did was used the existing transformers, methods and I just wrote a new one for the feature they requested, it worked flawlessly without a single issue.

So, their existing code had issues and they counted that into my assessment and said they'll reduce the salary promised on their job listing by 40%.

So I first said yes, I was just looking that hike my my salary, later to omly realise, I keep seeking for validation when working there rather than working for shipping features.

So, I actually turned it down.

Did I do the right thing?