Obviously, I am not a fan of backups for cloud-based applications like Exchange Online. However, the good news is that there are offerings available that can handle Exchange mailboxes etc. The problems all lie with the integrated Office 365 apps like Teams and Planner. If you do not want to backup them, then ISVs like Spanning can do a job for you. Beware of the cost and be ready to amend your processes to handle restoration of data.