Fortunately (and unfortunately) EndeavourOs is a terminal centric distro.
This has been discussed much before.
As far as I understand there are a few apps that are like text based front ends that are supposed to run fine.
There are lots here in this thread Pamac/Octopi/Pacseek Alternatives- To AUR or Not to AUR? I tend to like somehow pacseek. but didn’t try it even once, I am OK with yay.
by the way I have seen a nice app on CachyOS that I liked much better even than octopi which is “CachyOS Package Installer”
I am just playing a bit with CachyOS on a spare machine.