Wordpress debuggin

Hi there, my Wordpress site crashed and I have no time an not the skills to fix it. I need someone understanding deep coding and debugging. If we work well together you could also optimize my site and give it some kind of update, but get it running is more important right now. The update will be an extra project with extra payment. I updated the plugins and due to this process the whole sept crashed, then i installed an old backup but this is also not running, i can not stat Elementor and not see the preview. Uncaught Error: Call to undefined function astra_get_tablet_breakpoint() in /mnt/web518/e1/26/510611326/htdocs/WordPress_01/wp-content/plugins/astra-addon/addons/sticky-header/classes/dynamic-css/[login to view URL] Stack trace: #0 /mnt/web518/e1/26/510611326/htdocs/WordPress_01/wp-includes/[login to view URL](287): astra_sticky_header_account_dynamic_css('#content:before...') #1 /mnt/web518/e1/26/510611326/htdocs/WordPress_01/wp-includes/[login to view URL](212): WP_Hook->apply_filters('#content:before...', Array) #2 /mnt/web518/e1/26/510611326/htdocs/WordPress_01/wp-content/plugins/astra-addon/classes/cache/[login to view URL](81): apply_filters('astra_dynamic_c...', '') #3 /mnt/web518/e1/26/510611326/htdocs/WordPress_01/wp-content/plugins/astra-addon/classes/cache/[login to view URL](358): Astra_Addon_Cache->get_dynamic_css() #4 /mnt/web518/e1/26/510611326/htdocs/WordPress_01/wp-content/plugins/astra-addon/classes/cache/[login to view URL](108): Astra_Cache_Base->enqueue_styles('addon')