TOPIC: How to scroll to custom anchor on the page

ok, I think that I understand now
If you want to set up the scroll to top button to link to your custom anchor, this is not possible.
You can disable it from the plugin options, then create your own button with custom link and place it at the same place

Can you develop this function? How much it will cost?

if you want a custom development, please contact me by email to check this together

Are you using template-creator-CK?
If so, it could easily be fixed with some custom block + custom css.