bazzite is fedora based? If so, your filesystem is btrfs and your /home is a subvolume, same as your / (root). you can install a new operating system in a btrfs subvolume (e.g. /blendosroot), then have systemd-boot or grub mount it as root and mount your existing home from it.

sadly, there’s no noob-friendly way to achieve this, but if you’re adventurous, you have enough search terms to make it happen.