There is no "Linux UI" per se, the closest thing to it is Bash I guess. I find it important to make people understand that GNU/Linux is not bound to any particular GUI like Windows or MacOS are. With them, their less knowledgeable users equate the GUI to the OS, which is fair because they are so tightly integrated and not changeable. But for GNU/Linux, the visual UX+UI are entirely modular and not part of the operating system itself. As I said, the Bash shell may be interpreted as a kind of UI standard for FOSS Unix and Unix-like systems, but it's also not necessarily required in that it can be replaced with another shell program. Of course, not knowing you I cannot tell how experienced you are with GNU/Linux, so you could know all of this already, therefore don't feel like I'm trying to belittle you or anything, this is meant to be genuinely helpful by giving people that have no prior exposure to GNU/Linux some glances into what makes it special.
Edit: scratch that last part, I've just now noticed that you are the same person that said they had already transitioned partially