Recuperación de la partición de OS X tras un error de volumen FFFF y un error de adición de gpt

Actualmente tengo un rMBP de 13'' de 2014. Recientemente intenté eliminar una partición de Bootcamp en la Utilidad de Discos. Cuando traté de reiniciar mi sistema, no arrancó OS X (Mojave) y en su lugar sólo podía arrancar en la partición (vacía) de Bootcamp. He seguido los consejos de klanomath en este artículo y artículos similares. Me enteré usando dd if=/dev/disk0s2 count=3 | vis -c que mi partición original con el OS X de arranque era una partición APFS.

He intentado crear y volver a añadir el volumen a través de gpt add :

diskutil umountDisk disk0
gpt -add -i 2 -b 409640 -s 2542739416 -t 7C3457EF-0000-11AA-AA11-00306543ECAC /dev/disk0

pero la devolución decía algo así como "no hay suficiente espacio".

Cuando corro diskutil list ahora, obtengo la siguiente lectura, después de quitar el volumen 2, 3 y 4. El 3 era una partición Linux Swap y el 4 era Linux:

    /dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                 Apple_APFS                         967.3 MB   disk0s5
   3:                 Apple_APFS Container disk1         57.1 GB    disk0s6

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +57.1 GB    disk1
                                 Physical Store disk0s6
   1:                APFS Volume new mac                 30.4 GB    disk1s1
   2:                APFS Volume Preboot                 43.4 MB    disk1s2
   3:                APFS Volume Recovery                517.0 MB   disk1s3
   4:                APFS Volume VM                      1.1 GB     disk1s4

/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *16.0 GB    disk2
   1:                        EFI EFI                     209.7 MB   disk2s1
   2:                  Apple_HFS Install macOS High S... 15.7 GB    disk2s2

Entonces, sudo gpt -r show disk0 da lo siguiente:

      start       size  index  contents
          0          1         PMBR
          1          1         Pri GPT header
          2         32         Pri GPT table
         34          6         
         40     409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
     409640  863281248         
  863690888    1889311      5  GPT part - 7C3457EF-0000-11AA-AA11-00306543ECAC
  865580199        857         
  865581056  111523968      6  GPT part - 7C3457EF-0000-11AA-AA11-00306543ECAC
  977105024          3         
  977105027         32         Sec GPT table
  977105059          1         Sec GPT header

Ahora estoy atascado. He creado un volumen en el antiguo Bootcamp para al menos escribir este post (lo veréis como 'nuevo mac'). Se agradece cualquier ayuda.

Actualización:

Contabilización de la salida de sudo dd if=/dev/disk0 count=1 skip=409640 | hexdump -Cv :

1+0 records in
1+0 records out
512 bytes transferred in 0.000418 secs (1225033 bytes/sec)
00000000  d6 31 b5 5e 2d cf 09 45  01 00 00 00 00 00 00 00  |.1.^-..E........|
00000010  22 5a 11 00 00 00 00 00  01 00 00 80 00 00 00 00  |"Z..............|
00000020  4e 58 53 42 00 10 00 00  b0 67 d5 05 00 00 00 00  |NXSB.....g......|
00000030  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000040  02 00 00 00 00 00 00 00  e4 58 de be 33 c1 40 f1  |.........X..3.@.|
00000050  bb c7 0d b0 84 3d 7e 2c  90 4e 25 00 00 00 00 00  |.....=~,.N%.....|
00000060  23 5a 11 00 00 00 00 00  18 01 00 00 2c 6c 00 00  |#Z..........,l..|
00000070  47 9d 05 00 00 00 00 00  d2 0d 05 00 00 00 00 00  |G...............|
00000080  15 01 00 00 bb 5c 00 00  13 01 00 00 02 00 00 00  |.....\..........|
00000090  62 5c 00 00 59 00 00 00  04 b3 21 00 00 00 00 00  |b\..Y.....!.....|
000000a0  6a d5 0b 00 00 00 00 00  01 04 00 00 00 00 00 00  |j...............|
000000b0  00 00 00 00 64 00 00 00  03 04 00 00 00 00 00 00  |....d...........|
000000c0  fa 2b 05 00 00 00 00 00  fc 2b 05 00 00 00 00 00  |.+.......+......|
000000d0  86 d1 05 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000000e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000000f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000100  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000110  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000120  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000130  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000140  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000150  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000160  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000170  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000180  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000190  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001a0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001b0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001c0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001d0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000200