[giancarlostoro]

Possibly some lightweight custom DE based on Gnome's SDK, like tiling manager possibly, to give it a ChromiumOS vibe, but you can still use other utils from Ubuntu. But one that's not too focused on shortcuts only.

[piotrkubisa]

Could you expand what do you mean by "ChromiumOS vibe" (ELI5)? Do you look for a i3 inside GNOME Shell?

PaperWM[0] is an example of a tiled scrolling (window) manager based on GNOME SDK (Mutter) that runs in GNOME session.

[0]: https://github.com/paperwm/PaperWM