I have tried to use GIMP, but in my experience the UI is just so unintuitive and hard to use.
On top of that, this tool still sits along side other single purpose tools for scaling and rotating, which are the first results if you search "how to rotate in GIMP", so why should I even expect this tool to exist?
This is not intuitive UX which is "trivially different" to PS, this is a mess which can only be learned through laborious trial and error, or reading the documentation like a book.
[0]:https://docs.gimp.org/2.10/en/gimp-tool-unified-transform.ht...
That depends on which version you use. IIRC the version in the Ubuntu/*buntu repo's have a patch to bring the UI closer to PS, at least in appearance.
There are also some functions which you have to do differently in GIMP vs PS.