You can try “vanilla” Gnome which doesn’t have one:
sudo apt install gnome-session
I also suggest turning animations off in tweak-tool.
I am not familiar enough with Canonical’s customisations to know how to turn off the bottom bar. (I haven’t used it long enough to even recall there being one. I’ve always disliked Unity).
After installing you can switch between the desktops at the login screen by clicking on the cog icon.