thanks for tip. I was able to move the vendor store header to the “header”-section of my template by adding
do_action( 'woo_header_inside' ); to archive-product.php.
And changing the line in /plugins/wc-vendors-pro/includes/class-wcvendors-pro.php
$this->loader->add_action( 'woo_header_inside', $this->wcvendors_pro_vendor_controller, 'store_main_content_header', 30 );
One more question, can I copy my modifed class-wcvendors-pro.php-file somewhere inside my template folder? So that updating WCVendors-module wouldn’t override my changes in the future.