I have developed an idea on how to approach using ZBrush. I am still new to ZBrush as I started using the digital sculpting software months ago in 2025. While trying to get to know ZBrush, I have been struggling with establishing or distinguishing the difference between Symmetry [Transform > ‘Activate Symmetry’ (X)] and/or Insert Symmetry with Gizmo. I actually don’t know what is it called but I uploaded examples of screenshots from Maxon ZBrush page (Shane Olson’s playlist on creating stylized characters). Is it referred to as Local Symmetry? Feel free to let me know.
I think the thing you are alluding to, and judging by the screenshots you provided, is an IMM brush (InsertMultiMesh). In particular, by the screenshot, the one Shane Olson is using is the “IMM Primitives” brush. Regarding the symmetry… In order to use Symmetry, “Transform > Activate Symmetry” has to be turned on and choosing which axis you prefer and whether or not you want to mirror it. In the case of Shane Olson, Mirror will be active. This of course follows the Global axis center. If you have 2 subtools visible, and only one subtool is at the global center position, you would mirror symmetry on that subtool. If you want the symmetry axis to be centered on the second subtool, you would use L.Sym which would mirror the selected subtool and not use the Global Axis (see screenshots). HTH.
Thank you so much!