How to handle this situation?

I don't see any simple solutions here. No magic bullets.

Sometimes you can gain trust by completing projects on time and without complaints about "best practices", without trying to guard your work from others, etc. But sometimes that doesn't even work.

If you can't gain his trust such that he no longer feels the need to micromanage you, then it might be best to look for another job.

How to handle this situation?

I don't see any simple solutions here. No magic bullets.

Sometimes you can gain trust by completing projects on time and without complaints about "best practices", by helping others without trying to guard your "trade secrets" work from others, etc. But sometimes that doesn't even work.

If you can't gain his trust such that he no longer feels the need to micromanage you, then it might be best to look for another job.