I think CM is the number one priority. We have no top-two quality cover there at all.
Other positions which need addressing but which aren't as urgent are:
RB: (keep Semi and Murty, keep one, keep none?)
CF: we need to confirm whether Papa and Connolly will stay, if not we need to sign a pacy stricker.
I don't see CB as a weak area at all. Unless Jaidi is about to call it a day we have three players of good enough quality IMO. We also have the option of Thomas and Perry if we think we need further cover there and apparently Martin looked decent today. We might decide we want to splash out on another excellent player, a la Fonte, but it really isn't a priority IMO.