How do I give myself full read/write/admin access to Backups.backupdb on a old Time Machine HD

I have a hard disk which I don't want to use as a time machine anymore but I do want to delete files on there but I get:

The operation can’t be completed because backup items can’t be modified.

I disabled SIP but it still doesn't let me.

My goal is to delete files from this directory that I don't care about and archive it on Amazon Glacier or B2. I do not care for any other system files on there apart from the actual user data. I have nearly 50 backup snapshots on there and I can't seem to delete any files in there.

Is there a way for me to grant myself full access and just tell MacOS to give me full access.

Time Machine is very much an "all or nothing" black box, with very little customization or control.

Files inside one dated backup folder may actually just be duplicate catalogue entries to the same data as the same 'file' in another dated backup folder. That's why unchanged files don't take up more space each backup, and why TM folders are a huge mass of interconnected trouble.

Deleting files from one snapshot probably won't save you any space at all, until you've deleted them from all of the snapshots, so that all catalog entries to the file data are removed.

Normally, the way to delete files or folders from the entire backup is to do so from within the TM application itself. Right-click on the files, and select the option to delete.

My advice is to copy one snapshot of the files that you want to keep to another disk, and then delete the whole backup (or erase the disk).

Oh, and don't forget to re-enable SIP! ;-)