I just installed openHAB on a Raspberry Pi4. All is well. Notes on documentation when using Safari on a Mac.
You need to use http://openhabian.local:8080
The documentation does not mention the .local that I saw.
In the collection of documentation pages you can go to the related page and use the edit github link at the bottom to open a PR. That means open a proposal how to update the documentation.
Did you use Openhabian? or did you install it manually on your own Rasbian/linux install? This often has to do with the config of the DNS/Netbios name of the Pi and not the OS you are accessing it from.
I used etcher to build the image. I have never seen the Mac not need the .local.