Adobe has recently made some changes to Photoshop, which includes changing the undo shortcut and the behavior of the shift key when transforming layers.
Now, changing undo to match the behavior of other tools does kinda make sense. Yes, it will take me time to get used to it, but at least it's now aligned with the rest of the Adobe products.
The transform behavior is not something I can get behind though. Not only is it now inconsistent with Illustrator, it is inconsistent within the application itself.
Vector shapes require holding shift to scale proportionally, while raster layers (and smart objects, etc.) do not. Even further, grouping a vector layer reverses the behavior. Yet, if you have multiple vector layers selected, it works the old way. While if your selection includes a raster layer, it works the new way.
The result of this is that now I have to think about what type of layers I have selected, in order to scale something. This is not a case where people can "get used to the new way", because now I always need to worry about what type of layers I have selected.
This has a very real impact on my daily workflow, since now I can't be sure if my transform was correct or not. With the new version, I often find that I have mistakenly done the wrong transform (since I am in the habit of moving the mouse roughly to the same proportion anyway when scaling).
If any PS team members are reading this... I would urge you to reconsider this change. For the time being, I have to switch back to PS 2018.