The Jaguar port is not a port of the SNES port. It was built in-house at Id and was developed by Carmack himself. See Doom Wiki: https://doom.fandom.com/wiki/Atari_Jaguar
The SNES port runs on a bespoke engine written by Randy Linden. Whereas the Jaguar Doom is the basis for many console ports, SNES Doom is something of an (incredibly impressive!) dead-end on the Doom family tree.
The SNES port runs on a bespoke engine written by Randy Linden. Whereas the Jaguar Doom is the basis for many console ports, SNES Doom is something of an (incredibly impressive!) dead-end on the Doom family tree.