Dear @Dr.aka,
As I understand from your question, you have appealed the negative decision by BAMF and are as a result still in the asylum process. If your appeal is successful, you will receive a residence permit.
While you still in the asylum process, you have to request permission from your local Ausländerbehörde to work. You send them an application along with a job description filled out by the company.
If your appeal is unsuccessful, you will not be entitled to a residence permit according to section 18a without first leaving the country and applying for this permit at a German Embassy. There are few exceptions to this rule.
If not already done so, I encourage you to have your qualification recognized in Germany. Here is more information about this:
https://***.anerkennung-in-deutschland.de/html/en/index.php
The other option after a final negative decision, as referenced by my colleague @Meike and the previous answer she linked, is what’s called a Beschäftigungsduldung. There are additional requirements in order to obtain this type of temporary permit.
Best,
Éanna