I think this article is really helpful:
https://codex.www.ads-software.com/Dashboard_Widgets_API#Advanced:_Removing_Dashboard_Widgets
… basically, I just wrote a plugin like so:
# get rid of dashboard junk
function example_remove_dashboard_widgets() {
// Globalize the metaboxes array, this holds all the widgets for wp-admin
global $wp_meta_boxes;
unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_incoming_links']);
unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_plugins']);
unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_quick_press']);
unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_primary']);
unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_secondary']);
}
// Hook into the 'wp_dashboard_setup' action to register our function
add_action('wp_dashboard_setup', 'example_remove_dashboard_widgets' );
… then dropped it into the “mu-plugins” folder, and this got rid of everything except “latest comments”, “Right now”, and “Recent Drafts”.