Thank you for the answer. I see what happened then. It seems to be a bug.
I select a brush from the brush ‘favourites’ panel. Then i press on the brush tip icon to open the brush editor, but since the editor doesn’t automatically switch to the brush/group of the favourited brush, but stays on the last ‘directly’ selected brush, I can only edit it by pressing ‘edit current brush’ to edit it, or go on a hunt through groups to find the same exact brush. If I press ‘edit brush’ then the ‘save’ option is not present, just ‘close’. If I find it through groups, it has that option.
Edit: added a screenshot
https://pasteboard.co/Jv0Vf4M.jpgEdit2: seems like going through favourites isn’t at fault, it’s just the drop down ‘edit current brush’ instead of clicking on the brush picture doesn’t give the option to save. I think going through ‘edit current brush’ should give that option as well, otherwise selecting favourite brushes would need to open favourited brushes group and the brush be selected for quick visual clarity. I think the 1st option would be better for enhanced brush multitasking opportunities. But 2nd option may be more in line with expected logic.