Alma 10 only has Wayland, not Xorg. It’s a little difficult to install anything besides the official desktops. I’ve managed to install labwc and dwl, two relatively small window managers similar to openbox and dwl, but haven’t tried with xfce… You might be able to do it with some Fedora 40 srpms, (one can find some of them at rpmfind.net or pkgs.org) but a full desktop like xfce is going to be a lot of work. You might try requesting it from epel, see Requesting a new package in EPEL :: Fedora Docs but otherwise, you might be out of luck.