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.

The “correct” way to handle “static” addresses with dynamic prefix is using tokenized network interfaces (which is pretty much just the lower 64 bits of the IPv6 address). That will then be used for SLAAC in addition to the randomly generated address. The support for dynamic prefixes in firewalls on Linux and Mikrotik is however still pretty dire (obviously, as it’s not an enterprise feature). No clue about BSDs/pfSense