I'm one of the many recent immigrants from reddit so I guess that's my start to alternatives.
I don't think I can walk away from many of the American tech services I use, but what I have done is reviewed what I use, change what I can and walk away from what I can. I've curtailed my optional spend on American companies, goods, and services. We can all do that at least.
In the appearance settings (I think the first point, I just don't know what it's called in English) you can change it from top + sidebar style to just tiles on top, resembling Microsoft office's user interface. Makes it easier to transition.
Sadly, graphene doesn't support many banking apps, which makes for a shitty user experience. Liked everything else about it but not being able to access muh money on the go was a dealbreaker for me.