First of all, read the official WordPress documentation.

If you are not familiar with the wp-config.php file, you can easily use this plugin:
​ https://wordpress.org/plugins/debug/

Or manually add to the wp-config.php file this row:

If you need our help we will need some additional information.

You can find your System Info from your WordPress Dashboard’s menu by going to Elementor > System Info
The system info includes information about your Server and your WordPress environment.

If after a failed update your site shows: "Briefly unavailable for scheduled maintenance. Check back in a minute."

Don't worry, simply connect via FTP and delete the hidden file ".maintenance" in the site root and the website will reappear.

If you activate multiple plugins and your website handles a heavy amount of data, it would be better to increase the memory used by your WordPress project (40MB only by default).

https://docs.woocommerce.com/document/increasing-the-wordpress-memory-limit/
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There could be a JavaScript conflict with other Elementor plugins or you need to increate the memory used by your Wordpress. Try to increase your Wordpress memory limit.

https://docs.woocommerce.com/document/increasing-the-wordpress-memory-limit/