Version 3.0.2 activation error in WP 5.9.3, PHP 8.1

Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, non-static method WPi_DesignerButtonActivation::myplugin_activate() cannot be called statically in /home/o/odating/gartman-olga.ru/public_html/wp-includes/class-wp-hook.php:307 Stack trace: #0 /home/o/odating/gartman-olga.ru/public_html/wp-includes/class-wp-hook.php(307): call_user_func_array(Array, Array) #1 /home/o/odating/gartman-olga.ru/public_html/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters(”, Array) #2 /home/o/odating/gartman-olga.ru/public_html/wp-includes/plugin.php(474): WP_Hook->do_action(Array) #3 /home/o/odating/gartman-olga.ru/public_html/wp-admin/plugins.php(194): do_action(‘activate_wpi-de…’) #4 {main} thrown in /home/o/odating/gartman-olga.ru/public_html/wp-includes/class-wp-hook.php on line 307

P.S>.: Used theme “Chique Photography”