Move and transform tool are two different tools used for different purposes so they should not be combined. If you you don’t need “move tool” you can simply remove it from your toolbar.
And to give “transform tool” an icon you can use “SF symbols” app on AppStore to browse for SF symbols, and most of them can be used to give different tools customized icons, you simply have to rename the tool to the according SF symbol name and it will change to that icon. For transform I can recommend “skew” symbol. I attached screenshot so you can see how it looks.
Hope that helps.