How to automatically add articles in Google Scholar profile for journal?
In the comments, you list two examples:

Robotics (by MDPI), and
JEEECCS

Interestingly, Google Scholar (GS) profiles are meant to showcase authors' research, and not journals' research. (Cf. GS' self-description.)
Consequently, GS contains a function that can algorithmically add new publications to your profile based on author names. But it does not provide such an automatic function based on journal names.
Thus, if you maintain a Google Scholar profile for a journal, then you need to add all publications manually.