Very beautiful, Logan. I think hollies would look great but most of them seem to get to 15' or 20' high. Hoping for something closer to 10 ft. in height tho so as not to grow into neighbor's hardwood tree and also be easier to prune. My tea olives need to be pruned and it's going to be a bear! Will have to hire someone. I have a feeling I will end up going with an evergreen viburnum to keep the height down.

That is a conversation/communication I have with customers before setting. In some cases it is better to go point to point (flat) on a wall with exposed edge like that And live with and out of plumb condition. (I still would try to shim out backer board/kerdiboard the back corner as much as possible to plumb so the cuts look uniform in the back corner. As long as you have a flat plane on the wall you are good usually) Nor sure but looking at the pic....could be the pan liner was folded up at the bottom or something like that which caused the bottom of the wall to stick out.... so if you went plumb from that spot... yes you could be way out there at the top. Not sure of the methods used. Sometimes I have had to plane the studs to accommodate this. (You have to also take into consideration if you do this....whether or not there is enough adjustment for a glass door if you are getting a shower door kit from a box store. They only usually have a tolerance of about 3/8” or so. Anything more than that and you have to usually have a glass company make custom doors....which is way more expensive.) Obviously you would have had to redo the entire plane of drywall on that wall and not just in the shower to make totally plumb. Otherwise the transition would look bad. Some times that is unrealistic. Especially when a vanity or door or window is on the same wall/plane Because it would throw everything else off. But this should be communicated to the contractor and/or homeowner so you can manage expectations. Bottom line is that this looks unacceptable and I don’t see that being remedied by skimming more drywall mud. Then the ceiling line is going to have a big wow in it.

My take is the installer did a poor job of measuring. Can it work with that opening, certainly, but you will need to pack that opening in with some solid blocking but then you will need to figure a way to hide the blocking which kind of defeats the purpose of the custom ordering to fit the opening correctly. Up to you but I would think about making the installer reorder a larger window.

that's a pretty good match with the veining. can you back up at normal viewing distance? take another picture. were these tiles? what was specified in the contract or work order? Or did you just leave it to chance?