I’ve found Calamares can fall over if you’re trying to install to pre-determined partitions. I’ll generally clear the drive I’m installing to of any partitions at all, and let Calamares do it all during installation, which normally works fine then.
you need to reboot to LiveSession if you chancel installation, it can cause issue like this.
And clear partition you want to use before is also helpful in case there was another Linux installed before.