Will there be support for launching in Gnome Boxes?
Platon workaccount
1

Platon workaccount

This more of a question of is your Gnome Boxes configured to boot EFI?. I don’t use it but from what I understand it uses libvirt like virt-manager does so it’s a GUI for QEMU, therefore you need to follow the steps to boot EFI systems with QEMU.