This css snippet remove the “all properties” icon from the sidebar:
.workspace-tab-header:is([data-type="all-properties"])
{
display: none;
}
If you have never dealt with css snippets in Obsidian before, the official documentation has instructions on how to use them: CSS snippets - Obsidian Help
But the result is ~ the same as if you just disable them in the settings, as mentioned above… So it seems to me that if you don’t need them at all, it’s easier to really just disable them…