Use next algorithm to define what exactly does not work on your WordPress site after any changes with core, theme or/and plugins:
- create site duplicate using plugin https://wordpress.org/plugins/duplicator/
- create test subdomain on your site using hosting panel
- install duplicate bundle on your test subdomain
- on the test sub-domain deactivate all plugins except one main plugin (even change wp theme to default), for example WooCommerce
- one by one activate plugins and check functionality on the place where you found the issue, maybe you will have to each time make hard reset of the browser cache
- also test for conflicts your site cirrent wp theme - change theme to any default theme
Also in browser chrome press F12 to see js errors in console after each plugin activation as js+php errors from another plugins which can prevent functionality for another plugins. Do not forget to disable all kind of caches if they are enabled on your hosting.