Recently did that job on a Miele fridge. The new seal from Miele came with fitting instructions, and the job was straightforward.
One slight mystery - the instructions mentioned screws holding the seal in place. None on the fridge, and none supplied with the new seal, so I added a few 1/2" s/s self tappers. May not have been necessary.
seal most likely has a magnetic strip all around, right?
I couldn't get a new one for my WEACO and tried the main hardware store that sells and maintains food related h/w for restaurants, patisserie et al.
took the old seal to them built an indentical for 30odd euro iirc. cut 45deg at the corners and thermoplast sealed it somehow.
Door out job for sure btw!