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.
Hey, just a tiny note: static and dynamic addresses aren’t mutually exclusive. You can let SLAAC do its thing AND also set a static address on your server. Remember, IPv6 works best when you aren’t afraid of adding more addresses.