Upvote:2
ยง18c (Aufenthaltsgesetz) implies, indirectly, that if the person remains in the country for a specific amount of time: the visa can only be renewed when the foreigner has been outside the country the same amount of time that they were inside the country during the previous visa.
Since you are at present a full worker, I would suggest asking the Embassy/Counsulat how to look for work under such a constellation since ยง18c does not seem to be applicable.
One form of the question could be: can a tourist come for one for a job interview and then return back to his residence country until the next interview?
If you are a citizen of a country that needs a 90/180 visa, then could you apply for this for this purpose?