Fixing a poor drywall patch job (nothing new in this house)

It's no plastic grocery bag filled with paper towels and covered with caulk, but the loose 2x4 with a piece of drywall attached to it wasn't very effective either (left picture). I cut out a bigger piece of the wall so that I could attach a custom cut piece of drywall to two of the wall studs (right picture). After that, I put spackle in the gaps and once it was dry, I sanded the wall as flat as possible before priming and painting. It's not the best job I've done on wall repair, but it's behind the toilet and it's the pretty good work for having to maneuver around the water supply for the toilet.

I had two other main wall repair projects in the bathroom:

There was a chunk of wall broken next to the tub that was too big for spackle to fill. I used Plaster of Paris to fill in the gap of plaster that was missing. It took a while because plasters has to be applied in thin layers, letting each layer dry in between. Then, that had to be sanded too.

There was also a smaller hole in the wall next to the door where the baseboard had been. I used another mesh patch and spackle to fix that hole.