External disk is hijacked by fsck when plugged in to Macbook
The two items that come to mind are getting software that can try and repair the disk structure and prevent the mounting like Disk Warrior or connecting the drive using a USB write blocker / forensic adapter so that the disk just presents as read-only so you can get any data off it.

Then, you would wipe the drive if you can’t get it sorted. The native tool will choke on fsck even if you disable the automatic check when it comes time to mount the drive normally.