Ukelele not working on High Sierra
You should have no problem making Hungarian Qwerty work. Have you verified that the correct layout is showing in the "flag" menu at the top right of the screen when you are trying to type, like this:



To see the "flag" menu, you check the box for "Show Input Menu in Menu Bar" in system preferences/keyboard/input sources.

(Selecting something in system preferences/keyboard/input source does not accomplish anything other than show you a picture of the layout).

Ukelele is for making a custom keyboard layout.  Do you really need to do that for some reason?