You can hide the Quick Search Bar on the main page by editing the code.
Follow the instructions below:
1. Please take a backup of the files that you are about to edit before any updates.
2. Login to your admin dashboard.
3. Navigate to Appearance->Editor. On the right panel, select Main Index Template (index.php).
4. Delete the third line:
<?php get_template_part(‘section’, ‘upcoming_search’); ?>
5. Update the file.