I hope I have created the link correctly.
I found this post today attempting to do the same thing as Profile - Elegant_Emperor - Zorin Forum (? Link again)
After achieving this with extension manager I happened upon a Zorin 18 core native remedy for this task and thought it may help others.
Zorin Appearance – Interface – Taskbar Settings - Position – scroll down to the line that reads Right box and uncheck the visible tab