How to resolve a fatal error with incompatible with PHP8?

This plugin is incompatible with PHP8 along with checkout for payment solution from Nets Easy. Hope this can be fixed as soon as possible as PHP7 is nearing the end of its life.

[11-Mar-2022 09:37:50 UTC] PHP Fatal error:  Uncaught TypeError: Unsupported operand types: string * int in /home/alfadisplay/public_html/wp-content/plugins/product-quantity-for-woocommerce-pro/includes/class-alg-wc-pq-messenger.php:87Stack trace:#0 /home/alfadisplay/public_html/wp-content/plugins/product-quantity-for-woocommerce-pro/includes/class-alg-wc-pq-core.php(3048): Alg_WC_PQ_Messenger->print_message('step_quantity', false, '', 3, 6601)#1 /home/alfadisplay/public_html/wp-content/plugins/product-quantity-for-woocommerce-pro/includes/class-alg-wc-pq-core.php(2381): Alg_WC_PQ_Core->check_step(Array, 26, false, false)#2 /home/alfadisplay/public_html/wp-includes/class-wp-hook.php(307): Alg_WC_PQ_Core->check_order_quantities('')#3 /home/alfadisplay/public_html/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters('', Array)#4 /home/alfadisplay/public_html/wp-includes/plugin.php(474): WP_Hook->do_action(Array)#5 /home/alfadisplay/public_html/wp-content/plugins/woocommerce/includes/class-wc-checkout.php(1163): do_action('woocommerce_che...')#6 /home/alfadisplay/public_html/wp-content/plugins/woocommerce/includes/class-wc-ajax.php(461): WC_Checkout->process_checkout()#7 /home/alfadisplay/public_html/wp-includes/class-wp-hook.php(307): WC_AJAX::checkout('')#8 /home/alfadisplay/public_html/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters('', Array)#9 /home/alfadisplay/public_html/wp-includes/plugin.php(474): WP_Hook->do_action(Array)#10 /home/alfadisplay/public_html/wp-content/plugins/woocommerce/includes/class-wc-ajax.php(90): do_action('wc_ajax_checkou...')#11 /home/alfadisplay/public_html/wp-includes/class-wp-hook.php(307): WC_AJAX::do_wc_ajax('')#12 /home/alfadisplay/public_html/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters(false, Array)#13 /home/alfadisplay/public_html/wp-includes/plugin.php(474): WP_Hook->do_action(Array)#14 /home/alfadisplay/public_html/wp-includes/template-loader.php(13): do_action('template_redire...')#15 /home/alfadisplay/public_html/wp-blog-header.php(19): require_once('/home/alfadispl...')#16 /home/alfadisplay/public_html/index.php(17): require('/home/alfadispl...')#17 {main}  thrown in /home/alfadisplay/public_html/wp-content/plugins/product-quantity-for-woocommerce-pro/includes/class-alg-wc-pq-messenger.php on line 87