Tried latest April 22 isos a few days ago, still no luck.
Just checked and confirmed that Calamares in the build on April 15 is able to proceed, although it complains about not being able to find internet connection. The latest build on April 21 won't allow Calamares to proceed at all.
For latest isos (at least KDE, haven't tested Xfce or MATE), when Calamares is launched, it says "users@users" module cannot be loaded and we are unable to continue on installing the system.
March 28 iso fail to boot
MATE iso uploaded on April 10 is not working
The latest iso file "deblinux-x64_2020-12-15_1022.iso" is not working properly. I am unable to boot up the system using neither BIOS or UEFI.