I downlooaded the July testbuild (siduction-2025.1.0-Shine_on-kde-amd64-202507011840.iso 2025-07-01 20:49) tonight and attempted to install it in a VM. It installed fine, but failed to boot after installation. I tried with and without EFI enabled. Got the same error with both installs, You need to load the kernel first.
The one I have downloaded siduction-2025.1.0-Shine_on-kde-amd64-202503241412.iso installs and boots just fine.
I tested it with qemu, latest kde-test-iso https://testbuilds.siduction.org/kde/siduction-2025.1.0-Shine_on-kde-amd64-202507011840.iso.
Installed it in the VM, reboot, login, no problem, did an apt full-upgrade afterward, reboot again. No problem,
So I can't confirm it.
I was using virtual box. So far everything else worked there. I'll setup qemu/virt-manager after while and I give it a whirl there
Can confirm that the ISO does install in Virt-Manager/QEMU. Just something wonky in my VirtualBox install. Concerned me when others have installed fine, including the ISO from 202503241412. Sorry to have caused alarm.