I think I am having a similiar issue. I created a bootable USB drive with the Bazzite ISO loaded onto it with rufus. I then booted my laptop with that USB drive, and I am in the KSE desktop. I want to try Linux again, and also check out how game playing is on Linux, SO FOR KNOW, I was planning on using a USB3.2 external drive with a M2 NME drive in it. So, now that I am in KSE desktop on the laptop, I click on the Install to Hard Drive icon as I don't see any other option for installation. I get a message about Bitlocker being detected, etc, and that is as far as I can go. I can see the 1TB M2 drive as /dev/sdb. I just don't see a way of telling KSE to install to that instead of /dev/sda