You can't expand any panel to full screen in Resolve 16 like you can in Premiere Pro. You can expand the viewer to full screen with cmd/ctrl-F, and on the color page you can also get different viewer expansions with alt/opt-F and shift-F.
Beyond that, if a panel can be hidden, it's listed under the Workspace menu->Panels in Workspace, or by simply ...
I figured it out. The commands you're looking for are:
End to Playhead - in Application/Trim/Ripple
Start to Playhead - in Application/Trim/Ripple
Put them on some shortcut that is actually working on the german keyboard.
It seems like this key simply doesn't work on German keyboards.
It's probably because you have to press Alt-Gr to get the "" sign on a German keyboard, and the software doesn't accept that additional key.
You can, however, redefine this function to another key. In contrast to some documentation, this cannot be found in the project settings, but ...