@yech1990, it looks like you don’t have QIIME 2 fully installed, because R is missing from your conda environment. Can you please try reinstalling QIIME 2 following the instructions in the install guide? That should get you everything you need to run dada2 quality control.
However, before performing dada2 quality control on your joined sequences, you should read this post. Even if dada2 successfully processes your sequence data, the results may not be scientifically valid.