after updating some plugins I found the wordpress blank admin panel.

Later to solve the problem I restored a previous backup but it didn't work, I disabled the plugins and the themes, it didn't work.

How can I correct it? The site runs, but I can't access the admin panel, the logs give me this error:

Got error 'PHP message: PHP Fatal error: Uncaught Error: Call to undefined function wp_next_scheduled() in /public_html/wp-admin/admin.php:96\nStack trace: /public_html/wp-admin/index.php(10): require_once()\n#1 {main}\n thrown in /public_html/wp-admin/admin.php on line 96\n',

I thank anyone who can help me