Work permit application process - a real story? (Istanbul)

Can someone tell their experience/learnings for application process with a positive result i.e. obtained work permit?
I am sure several in the IN network by themselves managed to get a Turkish work permit for a ”normal” job. It would be good if a brief step by step overview incl. actual effort, the time line, cost/fees, challenges (if any) and learnings? (Let's assume you started out with a residence permit)

Secondly, can someone confirm if it is possible to get a work permit without actually having formally landed a job in Turkey first? I am asking because I have noticed that some headhunters/recruitment agencies do not accept CVs/applications unless you have a work permit which means they most likely only can hire expats already with a job in Turkey.

Finally, what is usually the cost if you pay a turkish service provider to manage the whole work permit application process?

In advance, I appreciate this great forums good advice.

Best regards

Per

Here is a URL to one formal description of the application process, but it would be good with a "real life" story in addition:
Protected content

Perhaps someone here could share even better links?