Pro version is almost the same as Core version.
It comes with some preinstalled apps which can be easily installed from Software. As I already explained, layout can be changed by installing custom dock such as Plank.
Most of us purchase Pro version in rue of donation to support Zorin developers (which consist of only two people).
You can learn a great deal about Linux just by exploring and customizing your desktop. I would encourage anyone to go for it.
That being said; if you want preinstalled with expertly configured layouts- Pro is the way to go. And it supports development.
Or... you can do both. Get Pro- and customize it.
OR... (lol) Customize Core and use the Donate button in About Zorin to kick them a couple of bucks, too.
Linux. It has Options.
Yes i agree with you...normally i try and ending reinstalling OS ahhahaha
But sometimes works 
I have done this a lot, too.
But as time went on, I ended up reinstalling less and less.
Yes it is possible to upgrade core to premium.
I am afraid that is not the case at the moment.
Core to Pro upgrade requires clean install (that what I did a few weeks ago myself).
Are you sure ?
YES.
If you are still in doubt, you can ask @Aravisian or @zabadabadoo
There was a talk of providing an upgrade path from Core to Pro version but I have no idea when that will happen.
Currently, the do-release-upgrade option or Direct Upgrade is unavailable on Zorin OS. In fact, aside from Ubuntu, very few non-rolling releases offer one. That Zorin OS has tackled the task of making an option like this is impressive, to say the least.
Please reference here as this issue has also caused some consternation in the past, such as users being Misled into believing they could upgrade on Reddit and destroying their systems.
That being said...
While there is no upgrade path, a user may take Zorin OS Core or Zorin OS Lite and install all the applications and create the layouts that come with Pro. In this sense only, a person can indeed "upgrade" their system to a version of Pro of their own making. Which... Is what I do with every release, you could say. Because I change a lot of stuff. 
Nah i am not, thought because linux is doing everything with sudo commands maybe there was a way to add the premium stuff via a command line.
I really wish there is such thing.
I preserved my Home directory but still took me almost half day to get everything in a right place after the reinstallation.
The software that comes with Pro can, indeed, be installed with command line.
For example:
sudo apt install barrier
The layouts cannot- you would need to install the base components and then configure them youself.
Well i don't care haha...i am happy with my core version and cinnamon 
But you could make a quite similar layout if not exact, using Plank, no?
Yep. Or Cairo Dock.
I did not know it is still available.
I switched to Docky/Plank quite a while ago because Cairo was a bit too heavy.
Cairo Dock does indeed look quit nice. The one from elemantary os i don't like, it's more like a big bar with icons on it. So ugly! 
You can experiment with your layouts from the taskbar settings. It is pretty easy to center the menu and icons like default windows 11 if you wish.
Aravisian is right, if you want to learn some Linux, and you have the time to do so that is, you can mess around with Plank. (Just don't walk the plank and jump into Reddit where all the sharks are)
OR......................................
You could just buy Zorin OS 16 PRO like I did, and get everything already installed, ready to go for your convenience. But best part is, you supported the dev's. And for that, I will thank you. 
Considering windows still costs well over a hundred dollars (people don't normally see the price tag because it's installed on the machine already), the 40 for ZorinOS is a steal. Save a little and then purchase.