How to mount/access RHEL8 (boot) disk contents from new RHEL9 system

Hi All,

I realize I created a significant problem for myself by simply removing the NVMe SSD that contained my RHEL8 system and replacing it with a new NVMe SSD card that I installed RHEL9 onto, and didn't first copy/backup my RHEL8 drive content but simply installed in into an external USB housing. Now, when I insert the USB with the old RHEL8 drive in it, I can't access its content so that I can copy it to the RHEL9 drive.

So far, I haven't touched the RHEL8 drive other than to plug it in and look at what's there with the Gnome Disks utility, which shows three partitions: a FAT32 EFI system; a 1.1Gb XFS partition; and 1.0Tb LVM partition. Only the XFS partition is mounted, but it only contains the linux system and not any of my files. Also, if I recall correctly the RHEL8 system had two LVM partitions rather than one as Disks shows.

I desperately need to access my data from the RHEL8 disk so that I can transfer it to the RHEL9 system. I (obviously) know next to nothing about disk or LVM management, so I'm completely stuck. Is there any way to dig myself out of this situation?

Thanks, mitch