Good afternoon, please tell me, can I somehow configure these elements through the graphical shell?
There is the customcss app:
Normal theming lets you change the colors and the logos, with the customcss theme you can go a bit beyond that (especially hiding elements).
If you want to change icons, I’m not sure if you could do this with your own app (so you don’t have to manually change code after each update). Perhaps someone with more knowledge of code can help you out here.