I verified the iso file and everything was good (I did so on Windows 11). I used this mirror (mirror.leaseweb.com/devuan/) to download this iso (devuan_excalibur_6.1.1_amd64_netinstall.iso) on a usb stick.

I'm trying to use those commands you mentioned (alt-F4 et al), now with a re-downloaded iso and a new day/boot, but it won't do anything (it also turned off num lock and won't let me turn it back on for some reason, or at least the light on my keyboard turned off and won't turn back on). I did see it do one to three things real fast (grey box that filled up), but then it stopped after that.

I'll keep it on for a bit to see if maybe it'll continue, but then I'll try expert install like you suggested.

Edit: After some time, now all my lock keys don't work, or at least don't light up.