Dean, you might try creating a symbolic link to your backup folder in your Users\ [UserName]\ OneDrive\ folder. That way OneDrive *sees* the backup folder and will sync it to the cloud.

tenforums.com/tutorials/131182-create-soft-hard-symbolic-links-windows.html

Dean, I just created a onedrive backup profile and although it accepted the custom folder location it did not enumerate the and include the subfolders of the Onedrive folder... so when the plan was manually started nothing was discovered in the local subfolders of the Onedrive cloud storage... altered the plan to backup the Public subfolder which holds 105MBytes of files and again not one file in that folder was included in the backup set... so looks like that part is broken... not sure why one would want to backup what is usually regarded as a backup location...
TK

"... you do not need a local client exposing the storage to ransomware"

You can follow the 3-2-1 rule, with local storage disconnected except when transferring data to it. Win11 Storage Spaces will also let you create a mirrored drive pair -- works with a ~$25 USB dock -- for a poor man's NAS. Unfortunately cloud backup is not viable for a huge number of Americans using cable broadband, because the upload speed is often beyond dismal -- it takes me days for a couple hundred MB.

backblaze.com/blog/the-3-2-1-backup-strategy/

mike, disconnected USB storage is of no use with real-time backups... mirrored drives do not protect against malicious activities as the malicious activities are mirrored also.... Thankfully I am not an American user using a badly provisioned cable provider.... for system backups cloud pricing is prohibitive as well as the issue with upload time but for real-time protection of Documents and Pictures hierarchy with the necessary folder exclusions for bad programmers misusing the Documents folder for stolen FFMPEG.EXE installations and workspace messing up the windows environment it is possible create a free 15Gig google drive account and never use the email account associated with it to hold encrypted and compressed backups of essential documents and pictures and be fairly certain google will keep it's own service properly backed up with necessary redundant storage. There are plenty of cloud options provided including WebDAV for that subgroup of providers.

FWIW I don't like the focus on automation -- it's harder to work with if you do backups manually, missing several options found in many competing products. AOMEI Backupper isn't bad, & you've got a free option in case, but it won't do everything I want/need. Macrium Reflect up to version 8 is great -- after v. 8 they changed the backup file format, and since they no longer offer a free version, it's cost prohibitive if you have several devices to back up. O&O DiskImage Premium & Pro are just about as good, and they offer a 5 PC license option that's cheap when on sale.