Does anyone have a video or guide for replacing the rear wiper motor assembly on a 2015 impreza hatchback

I have a 2015 subaru impreza hatchback I had the rear wiper get stuck on a bike rack and it seems to have burned out the motor. I can find the parts but I dont see any good video tutorials on replacing the rear wiper motor assembly only dumb vids of replacing a wiper blade

I am taking over Oscar the Grouch, take off the interior panel, cannot think it could be that hard.

Just get a copy of the service manual for your model. Do some googling you many find it for free, otherwise its not that expensive and fantastic to have if you like to do work on the car yourself. I just had to remove mine from my 2011 Forester, in order to install a back up camera. It will show you the clips and screws to remove, and how to remove the rear wiper arm. It required more dismantling than doing it on my former Nissan, but only a few minutes worth.
For the Forester there are 3 clips and a screw to remove behind a plastic cover for the handle on the bottom, but you have to start from the interior top, and remove it and the top sides to remove the section covering the wiper motor. Also two push pin screw fasteners top of both sides of the lower cover. I am sure the Impreza hatch is similar.

Tester

Fortunately on the 2011 and I suspect a 2015 they used a 10mm bolt to attache the wiper arm, the same as for the 3 bolts on the inside. Pulling as you did on mine would have broken the rear cover. I strongly recommend identifying all the fasteners before the hard yank.
Not sure for the Subaru but when my X trail wiper motor failed, it was because the pivot arm seized in the armature due to accumulated crap. Opening the motor, and removing the spindle arm, sanding it smooth again and lubing it up with good bearing grease, freed up the mechanism and the wiper motor continued to work fine for more than 3 years prior to selling it. I suspect if your rear wiper motor was getting progressively slower until it seized, it would be a similar issue and a cheap fix. I did because on the X trail the rear wiper motor was dealer only and cost $479.

Would that video on a 2000 model forester be relevant for 1 2015 model ?

Yup pretty much identical. Nothing new about it, or the way Subaru attaches its interior panels.