MacBook Data Recovery

I have a MacBook Air 2017. Out of the blue, I opened the MacBook and was confronted with the question mark. The Mac would only boot in recovery mode. In internet recovery mode, I copied the internal disk (dd conv=noerror,sync) to an external hard drive. Whilst I did create a 250GB disk image, I'm not sure of the quality of it, as I received many ‘disk not configured’ messages in the process. With that disk image from the external drive in another MacBook Air 2017, I used hdiutil imageinfo which said there were seven partitions on the disk image. I then used test disk/ file system utils which showed two partitions an EFI partition and an APFS. I created an image of the APFS partition which was 250GB but when I run **photorec** on that (writing to a second external hard drive) it hasn’t recovered any files. Any advice on next best steps or things that I need to do/ haven’t done. Would be hugely appreciated. Edit: A previous attempt at running photo rec on the full disk image yielded a 250GB plist file. Edit2: I can now use target disk mode to see the disk on another MacBook. However it fails to mount. DDRescue currently running and making slow progress.