Multi head X like this? https://www.duskopijetlovic.com/x11/unix/howto/dotfiles/2021/12/13/xorg-x11-multihead-two-separate-screens.html

I have that exact machine in my electronics “graveyard”.

Peppermint OS was my GO-TO for speed and driver support out of the box. You can also stick in a 2GB SODIMM of ram. It will only recognize 1.5GB but still 50% more ram.

J1900 has no hardware switch. Every packet goes through CPU, so even LAN to LAN uses processing power. Add pfsense to the mix and it’s probably choking.