Rear wheel bearings

Simple answer is "Not very easy"

I had to grind thru the outer shell on mine to get it out of the suspension side piece.

The bearing is literally pulls apart when the wheel hub is separated from the axle. At that point there is no going back because it is immobilized until the new bearing installation is completed.

I believe that my experience was more difficult because the new style BMW replacement bearings had been installed and they are slightly oversize for the press fit as originally designed. 200 hits with a 12 pound slide hammer puller did not move the bearing shell at all

After having to grind it out of the housing and off the hub the old style bearing that I purchased in the aftermarket went in like it was intended to fit

The fit is so tight with the new style bearing that BMW issued the dealers a new superduty tool set to remove and install them.

Mine had to be changed bacause who ever installed that bearing had failed to get it seated and it was rather noisy. I got a nice $6000 discount on a car that had been CPOd by a dealer and the auctioned because it sounded like a bad differential

Unless you have a fully equipped workshop, with a nice garage to work in, and a whole heap of enthusiasm, I would let the dealer do it for that money.
The job will probably last the life of the car and the job can become an absolute epic when it goes wrong.
Get a fixed price quote and point out your labour rate is on the 4+ scheme and you will not go far wrong.

8Tech.