The desktop editor has three helpers you can switch on or off independently. All three live in Settings under Editor.
Fixed toolbar
A formatting toolbar that sits in the editor header: text styles, checklists, tables, recording, drawing, highlights, attachments and the rest. Turn it off if you insert everything with the slash menu and want the header quiet.
Floating toolbar
A small toolbar that appears next to the text whenever you select some, with the formatting you are most likely to want mid sentence. People who format as they write tend to keep this one on.
Draggable blocks
A drag handle on the left of each block for reordering paragraphs, lists and images by dragging. With it off, blocks still move by cut and paste, the handle is just not drawn.
On mobile
The mobile editor keeps its single toolbar above the keyboard, which is not configurable. These three switches shape the desktop editor only.
The minimal setup
Some people turn all three off and drive everything with / and Markdown shortcuts. The editor works fine that way, it is a matter of taste rather than capability.