I remember my colleague who was DevOps guy (15+ years exp) in our one very good project about kids' edutainment.

He always breaks things & blames others when only he had admin access of the tool.

When client was very much interested in Android app, our that DevOps focusing totally on REST API & ignored Android app related DevOps tasks.

Our Android CI/CD was not complete till project ended. Due to his stubborn nature we couldn't take benifit of automation testing.

You can't tell him how to do any task, if you tell then it will be taken by him as an insult to his intelligence.

He would waste his 2 business weeks to find a way to do that task, then he would do some frugal trick half heartedly then he will leave it. Still he wouldn't accept your help due to his ego & he would work on tasks which he likes even though they are of low priority.

He was hellbent on cost cutting so he reduced caching availability to save extra billing, now we couldn't had enough speed for even 10 users to show recommendation feed by API.

Due to this our client couldn't show demo to angel investors properly & didn't get funding.

I don't how with such a bad attitude, he could survive so long.

He had plenty of training certificates (Salesforce etc.) with very little practical knowledge.

God save people of his current & future projects.