There is Terminal app with Fluent Design, but unfortunately there is no opition do download this app from Store, for some reason :/
He's using tmux for the split terminal screens, for the system stats i'm sure he's using htop, for the cows cowsay.
If you are looking for the app to communicate with the WSL instance, it looks very similar to FluentTerminal ( https://github.com/felixse/FluentTerminal )
IIRC Terminus doesn't use the Acrylic material, its use the native 'Aero' effect, wich lacks of the grainy texture and has a less blur amount.
So in this case FluentTerminal is a better option, because is built on top of the UWP Platform.
At least considering the Fluent Design.
I've been enjoying the new Windows Terminal Preview. Before that I would use XShell. If I'm going to run something like hyper or Upterm, I really want them to support PowerShell well if I'm running on Windows.
You can also check out https://github.com/felixse/FluentTerminal/