Oh FFS
There's really not that much different about S/4 over ECC from the user's POV. Sure, SAP keeps trying to push their idiotic web interface idea, which is not only somehow less logical in it's layout compared to the fugly AF SAPGUI, but also far less efficient since you can't have multiple windows open at the same time.... still, it's not that difficult to pick up unless you're someone who memorizes the what instead of learning the how. You can also still use the SAPGUI if you want. Probably safer to do so than the web version using a browser with who knows what extensions installed and other nonsense.