I might try the Fluxbox version because my pc only has 4gb non upgradeable RAM and Ubuntu is using almost 2GB just to run at idle with no apps running.
Wow, that's very low. I made a live usb of MX XFCE and one of Fluxbox. Running off the usb XFCE was using around 675mb and Fluxbox seeing 450. I then also tried Linux Mint Cinnamon and it was running at 745mb idle.
Fluxbox was a like too bare bones for me, XFCE was nice but Cinnamon is even nicer so for just an extra 200mb I went with Cinnamon. It's using less than half of what Ubuntu does and gives me everything I need.
But I think I'll run MX in a KVM VM just to use it, get used to it and see whether I might prefer it long term. I like that it uses less systemd.