Driver for Printer Brother MFC-9970CDW
https://support.brother.com/g/b/downloadlist.aspx?c=us_ot&lang=en&prod=mfc9970cdw_all&os=128
https://support.brother.com/g/b/downloadhowto.aspx?c=us_ot&lang=en&prod=mfc9970cdw_all&os=128&dlid=dlf006893_000&flang=4&type3=625
Sorry, I am new to Solus and like this OS a lot but unfortunately my printer is not on your list. Some other user asked for this driver, too.
I hope I will be lucky.
Thank you