So I have 2 drives, "SSD" where OS and everyday files go, and "Storage" where the bigger stuff is kept.

"Storage" was formatted NTFS. Once during a KDE Neon install, where you choose if you want the installer to manage and use LVM or do it manually...I accidentally hit "Next" with LVM selected on "Storage". I immediately realized this and cancelled out of it within half of second, no actual data was written. Then I chose the correct "SSD" drive and installed KDE Neon.

Now I basically can't access the drive from any OS. If I have it plugged in while trying to boot Neon, it doesn't start and kicks me out into intramfs because both SSD and Storage have the neon-vg and neon-vg-root partitions and it conflicts. If I start Neon with just SSD plugged in, and then plug in Storage after it boots, it shows up weirdly in Partition Manager where it doesn't list the actual hard drive but just two "neon-vg" entries for it. I can't mount it or do anything.

If I try to use DiskInternals Linux Reader in Windows 10 it can't open it.

I don't want to make it worse by playing around with in myself - would anyone that's knowledgeable on the subject be able to advise the best course of action here?

Thank you in advance.