We do not provide support for hacks, so use them at your own risk. If you're not comfortable with coding, we recommend against using this workaround.
Default Semplice functionality doesn't allow you to remove the Back to Top arrow, but you can do this with a tiny bit of custom code.
Adding in the custom code
Just drop in this custom CSS:
.back-to-top {display: none !important;}
If you want to remove the arrow globally, add it under Customize > Advanced > CSS Editor. To remove on a page-by-page basis, add it under your Page or Project CSS editor.
For more info on adding custom code to Semplice, follow this guide.
That's it! You made your Back to Top arrow disappear.