How can I override or alter a module's help text?
I don't recall doing exactly this, but I think you can use a hook_module_implements_alter() for this:

function MYMODULE_module_implements_alter(&amp;$implementations, $hook) {
  if ($hook === 'help') {
    unset($implementations['layout_builder']);
  }
}


This should disable layout_builder_help(), and then just yours will run.  A hook_help_alter() would be nice, but I don't recall ever seeing an issue for it.