I assume you have the new Z17 Core. I have Z16.3 Core, but should be similar.
EDIT 10/02/24 in response to @jayesh post:
Go to:
Settings>Appearance>Panel
Right click on the Taskbar
Select "Taskbar Settings"
then "Style" Tab
There you should be able to vary the "Panel Size" height setting.
The panel icons size will also change together with panel height to fit.
If Z17 Core Taskbar Settings>Style is different. Someone post a screenshot of that please.