How to completely remove the sidebar? [closed]

Looks like they are hard-coded into the sidebar. So you could manually remove them, but they’ll just return when you update the theme.

Best solution would be to make a child theme, if possible, and create a new sidebar without the unwanted widgets.

EDIT:

Remove

    <aside id="archives" class="widget">
        <h1 class="widget-title"><?php _e( 'Archives', 'adamos' ); ?></h1>
        <ul>
            <?php wp_get_archives( array( 'type' => 'monthly' ) ); ?>
        </ul>
    </aside>

    <aside id="meta" class="widget">
        <h1 class="widget-title"><?php _e( 'Meta', 'adamos' ); ?></h1>
        <ul>
            <?php wp_register(); ?>
            <li><?php wp_loginout(); ?></li>
            <?php wp_meta(); ?>
        </ul>
    </aside>

That should be sufficient.