In reinstalled macOS bigsur there no disk to select also in restore from machine there no disk to select.
iMac 21.5″, macOS 11.5
Hello, Reach555.
From your pics, I can see that the disk you want to install Big Sur on is the top-most device, the SK hynix SH920...
You will want to select that in Disk Utility and erase it. Name it "Macintosh HD". Format it with APFS and GUID partition scheme.
Then exit Disk Utility and select Reinstall macOS Big Sur. You should now be able to choose Macintosh HD as your install location.
Hardware problem: In reinstalled macOS bigsur there no disk to select also in restore from machine there no disk to select
