In Germany with Job seeker Visa + Unable to find job

As you have encountered, it is not asy to find a job (even in a sought-after category like experienced Agile Coach and Scrum Master) without German language skills. After all, you are automatically excluded from roles that require interaction with German customers, partners, suppliers or colleagues. This reduces your niche to very small to non-existent.
But after just three months, you are still at the beginning of a job search, which typically takes much longer - 6 - 12 months should be realistic in a specialized field like yours. (For comparison, I needed 5 months at the beginning of the year, despite being German and easily employable. I also sent out far more applications than you, leading to just two interviews.)
There are no headhunters who actively help you find a job. They are usually engaged by employers to fill vacancies and would deal with you only if there are fitting job descriptions in their pool at the time you approach them. You can find them through job listing pages like Stepstone.
There is, of course, always the possibility that you don't find a job and must return empty-handed. That's why you should have a plan B that you needed to describe in your motivation letter for the job seeker visa application.