yes the "familiesammenføring" visum gives you right to work full time in Denmark, and thats one of the often most difficult requirements for non-EU citizens to fulfill, but as said in your case where you have this "familiesammenføring" visa, you can work full time.
So your are right, if you meet the other requirements for being eligible for Unemployment benefits ("dagpenge"), you can have dagpenge.
However, if you have not been living in Denmark for the last 7-8 years, you must be aware thet there propably will be a new requirement from January 1, 2019. In the future you must have been living in Denmark or another EU/EEA country for 7 out of the last 8 years for being eligible for dagpenge.
You can read more about this new requirement here:
Anders Weber, www.a-kasser.dk