I've spun up a trial CAL and basic trial S/4HANA instance with a Windows Remote Desktop alongside it.
I am able to connect to S/4HANA via SAP GUI both in the Windows RD and from my computer on Ubuntu.
When I RDP into Windows, I'm greeted with Firefox showing the getting-started page, which has a link to SAP Fiori Launchpad (https://vhcals4hcs.dummy.nodomain:44301/sap/bc/ui5_ui5/ui2/ushell/shells/abap/FioriLaunchpad.html). If I follow that link, I get no response and an "Unable to connect" message.
C:\Windows\System32\drivers\etc\hosts contains two lines:
[Windows RD Internal IP] frontend.dummy.nodomain frontend
[Linux Internal IP] vhcalhdbdb.dummy.nodomain vhcalhdbdb vhcals4hcs.dummy.nodomain vhcals4hcs vhcals4hci.dummy.nodomain vhcals4hci
I've looked at a couple of different guides to this, and none of them seem to indicate that there is some "enable Fiori" step, they seem to just have you edit the hosts file then connect, but is there such a step that I'm missing?
Let me know if I can provide any more information!