This is what the default theme preview looks like
This is what my terminal looks like
I also recall the terminal having the transparency last time i used the live environment, but once installed it was just gray
The terminal transparency setting for konsole is in the settings hidden in the profile under “Edit color scheme”
So that was my problem, thinking the konsole’s “theme” came from the system theme. I booted the live environment on a VM and extracted its eos-live.colorscheme and EndeavourOS.profile from ~/.local/share/konsole/, copied to my Konsole folder, changed the profile and relaunched Konsole, now it is the same as the live environment. Thanks.