congratulations for launching the new version! Yesterday I tried to install on 2 notebooks and in both the installation presented problems, I attached photos of some errors. In both I have used elementary 5.1 and 5.8 and the test mode of 6.0 worked but still could not install
It cannot write to the volume because of some error with LVM. Go into the demo mode of the installer, open the terminal, and wipe the volume using the 'wipefs' command (sudo wipefs /dev/mapper/data_BLIn8 or whatever the original name/location of the volume is). For good measure, you might want to write a new filesystem (sudo mkfs -t ext4 -f /dev/mapper/data_BLIn8).