Unable to partition and install filesystem on san-connected mutipath volume

Title pretty much says it all. Using Ubuntu 22.04. I have a simple install going -> physical HPE DL360 G9 with two 2-port HBAs connected to an iSCSI switch, which in turn connects to our Nimble storage array. Below is what I've done: - Installed Ubuntu 22.04 and updated it - Changed the iSCSI initiator name in the initiator config file - Changed my NIC names to be understandable (en01 = mgmt0; ens1fs0 = iscsi-1; ens2fs1 = iscsi-2) and applied the changes - I installed a Nimble Linux toolkit which modifies iscsid.conf and adds multipath.conf "devices" section for Nimble devices - I then created two iface's with my 2 iscsi NICs and restarted both iscsid and multipathd services - I configured a Volume on my array and assigned access to it via the iqn of my server - I then performed a iSCSI discovery via iscsiadm, then did a login. At this point...all is looking good - I retrieved the wwid of the Volume connected so I can add a friendly name for it in the multipath.conf file. Still..all good here - At this point, I reboot the server to refresh everything and make sure my iSCSI target connection automatically reconnects, and it does. Still good - Here is now my issue. I run fdisk /dev/nimblestorage/ (this is I believe a symbolic link to the connected Volume) and go through the process to partition the disk. Simple process. But, at the end of it after I "write" changes to disk, I receive the following error or warning:

Calling ioctl() to re-read partition table. Re-reading the partition table failed: Invalid Argument.
The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or partx(8)

So, I do what the message says to do and reboot. I then attempt to put a filesystem on my partition/volume using the below command:

sudo mkfs.xfs -b siz=4k -m reflink=1,crc=1 -L test01 /dev/nimblestorage/

and receive the following error:

mkfs.xfs: cannot open /dev/mapper/: Device or resource busy

If I try this via /dev/mapper/, I think it works, but the storage doesn't show when running df -hT I can't do anything. I've been Internet searching all over the place and nothing I've attempted has worked. What am I missing? Is the issue multipathing? Did I not configure something? Really appreciate any help you all can provide. Even if I don't install the Nimble toolkit and just go by /dev/mapper/... , I get the same issues.