Assalamu Alaikum, I attend halaqas at my university weekly, particularly on the 40 hadith compilation of Imam an Nawawi. In the beginning, in unison, we recite Ratib al Haddad by Imam Abdallah al Haddad, is this a bidah? If it is, should I still say it but just out of sync and on my own?

‎Yes, reciting it in unison is a bid'ah, as Imam Ibn Baz said that remembering Allah collectively in one voice is from the innovations. Do not recite it on your own either, as he said the Sufi awrad such as al-Haddad's are not to be relied upon, and a believer takes his wird from what is reported from the Prophet ﷺ‎.