@kev If you don't mind a little bit of lua scripting, there is hammerspoon which is something you should definitely get. There are a few window manager-like scripts that people have made that may or may not help you with that. I was very surprised how powerful it is. For example, I'm used to my screen reader playing beep sounds based on the indentation level of the current line under the cursor. The Mac screen reader, VoiceOver, doesn't do this at all. But thanks to Hammerspoon this is now possible. As for moving the dock to the top of the screen, this should probably still work. Open a terminal and type: defaults write com.apple.Dock orientation top It might not, but it's worth a try. Just kill the dock process, or log out and back in, and it should move it if this wasn't broken recently.
@meena@kev I believe for that, you would need an app like Karabiner. You can enter a lot of accented characters in MacOS though by pressing them with opt. For example, for umlauts, I believe it's opt+u, then a, o or u.
@meena@talon@kev Using option and option+shift shortcuts should get you almost, if not all, the characters you would need with the compose key. There's a keyboard viewer in the keyboard settings that will show you what characters you are typing while you type.