Maybe htop? It’s pretty configurable and has decent bars for various resources.
Also if your reason for choosing pure TUI is just resource usage (and not the aesthetics of it / cool feeling / whatever else), then you could maybe look into running something like Sway or Xorg+i3 - those are very lightweight, well suited for single window usage, and open up a lot of possibilities for lightweight GUI apps.


Charles university uses and develops something called ReCodex, and it is available on GitHub. As a student, it was very nice to use.
https://github.com/ReCodEx/wiki/wiki