The documentation to create persistence leaves a few questions and requests for improvement, to make give some more background information for newbies to Kali and Linux.
To be honest: I am struggeling to create a persistent 32 GB drive based on the documentation.

In quotes you can find the current manual, I add my suggestions in single quotes. Hope this makes it easier to understand.
"you are running as the root user" > Suggestion: 'if you login the first time, you are the root user'

"your USB drive has a capacity of at least 8GB — the Kali Linux image takes over 3GB, and for this guide, we’ll be creating a new partition of about 4GB to store our persistent data in." > currently price for 8 GB drives are higher than 16 GB and many people just use 32 or more GB drive . As my stick has 32 GB, I am thinking about the minimum size of the Kali-Partition, as upgrades and additional tools also require some additional space. I would be happy, if the user could get some advice about the recommended size of each partition. My suggestion: adding a paragraph: 'Considerations on the size of the persistent partition: The Kali Linux image takes over 3 GB, for upgrades you will require additional xx GB, additional tools also require space. On 16 GB drives you should consider yy GB, above 32 GB you are good to go with zz GB.'

Step 1:
"This can be verified with the command “fdisk -l”." > > for Linux newbies it is not clear how to check this. I suggest to explain how to determine the position of the USB. I see the risk that otherwise on a desktop with several hard drives, someone will need Kali to repair the damage just caused. Suggestion 'The information on the disk, e.g. /dev/sdb, shoud match your stick in size and Disk model' >> Screenshot 1

Step 2: > I am lost here.
"First, let’s create the new partition in the empty space above our Kali Live partitions." > My Kali partition has only 2.6 G, which means not a lot of space for more tools. Wouldn't we first expand the partition to the recommended size mentioned above? As a second step I would use the rest or parts of it for persistence. Are there any suggestions available? Try and error is time consuming and I am willing to learn from others experience.

"end=7gb" > How is the end determined and what is the implication? The drive has 8 GB, why waste 1 gig? Which value should I enter using 16, 32 or more GBs? A suggestions would be great. Maybe an info how to use the whole stick?

"end=7gb
read start _ < <(du -bcm kali-linux-2019.4-amd64.iso | tail -1); echo $start
parted /dev/sdb mkpart primary $start $end"
Here my result: >> screenshot 2

My question: how does the Kali-image get on the stick? I guess that the new partition should start at the end of kali partition, right? How can I determine the exact position?
As I am coming from windows, I prefer GUIs to determine the correct harddrive. Can this also be explaind using gparted? For me it is very intuitive and similar to the windows manager.
I tried this way, but I have an issue with garted, as it doesn't show the drives >> screenshot 3. This is the first time I encounter this behaviour of gparted. Usually I am able to see the details of all drives. Any hint how to get full access?

Step 3 and 4 are afterwards strait forward.