I use controller mate, which is very nice in tuning the key mappings.
It's not free but really powerful and you should easily find a preset for eso on internet.
You can simply plug in the PS4 controller and it will work
You can then use the control settings to set up the PS4 controller exactly the way you want.
There are a couple of nice add-ons that help modify the console interface a bit too.
(If you are still having issues feel free to PM me)
You can have a look here : https://forums.elderscrollsonline.com/en/discussion/65578/how-to-play-eso-on-mac-with-a-controller/p1