(Im sorry to post, I just keep getting lost in terminology, going around in circles on YT and Reddit.)

Goal: I want to add one 200GB partition to /sdc as; A) I want to install a Ubuntu VM and have clones/backup. B) try out other containers on the remaining 100GB space (testing).
Possible Issue: I am currently using /sdc on OMV as a network shared drive (ext4). Would I need to resize /sdc1 partition or create a new partition?
Do I need to unmount /sdc in OMV till the 200GB partition is created? (I ask as I tried a volume on /sdc1 and I lost data)
Or
Do I make a LVM on /sdc from the Prox GUI? This would host the Ubuntu VM and clones.
Do I make a second LVM for my "test lab?"
ZFS?
Tertiary: I will use 10TB of /sdc to backup my media hard drive /sdb (currently on OMV as well). Should I stick w/ MergerFS or try ZFS to backup /sdb -> /sdc?
Does that need its own partition? or does ZFS "skip" the partition part?
I am open to suggestions (and links of course).
Thank you -

Goal: I want to add one 200GB partition to /sdc as; A) I want to install a Ubuntu VM and have clones/backup. B) try out other containers on the remaining 100GB space (testing).
Possible Issue: I am currently using /sdc on OMV as a network shared drive (ext4). Would I need to resize /sdc1 partition or create a new partition?
Do I need to unmount /sdc in OMV till the 200GB partition is created? (I ask as I tried a volume on /sdc1 and I lost data)
Or
Do I make a LVM on /sdc from the Prox GUI? This would host the Ubuntu VM and clones.
Do I make a second LVM for my "test lab?"
ZFS?
Tertiary: I will use 10TB of /sdc to backup my media hard drive /sdb (currently on OMV as well). Should I stick w/ MergerFS or try ZFS to backup /sdb -> /sdc?
Does that need its own partition? or does ZFS "skip" the partition part?
I am open to suggestions (and links of course).
Thank you -