Trying to understand booting

I'm pretty lost here and would like some pointers. I have an SSD (let's call it /dev/sdc) with both Windows 10 and Fedora 32 installed. Windows was not bootable since I installed Fedora because I guess it overwrote the MBR or something idk. So I decided to get another SSD (let's call it /dev/sda) to move the Fedora partition to.

I used clonezilla to copy the partition to sda, but I was not able to boot from the Fedora partition on sda (the new drive). So, I used clonezilla to clone the entire drive. I thought that would give me two identical drives, but the actual results surprised me:

• I could boot Windows 10 again. I guess clonezilla somehow fixed the Windows boot manager. It only seems to boot from sda, the new drive.
• Now when I boot Fedora, it seems to randomly choose one of the Fedora partitions to boot from. So for example when I run the command `mount | grep " / "`, it sometimes shows sda, and sometimes sdc.

I suspect the second problem has to do with the guid of the partitions being the same since they're presumably an exact copy of one another. I'm not really sure how that works though.

Also, it's worth noting that I don't think the Fedora partition uses UEFI to boot:

Code:$ efibootmgr -v
EFI variables are not supported on this system.Ideally the setup would be a UEFI partition on each drive, sda for Fedora, sdc for Windows. But I'm not sure how I can do that. I don't even what it looks like now since I don't know how to read the MBR or UEFI partitions and see what's inside them.

Thanks for your help!