Wordpress website giving critical error

One of our wordpress websites was giving a critical error, but only when trying to edit a particular page. A few days later, the admin for that site fixed it, probably taking help from some LLM etc - 

I enabled safe mode and also edited the configuration wp-config.php file, 

define('WP_MEMORY_LIMIT', '512M');

define('WP_MAX_MEMORY_LIMIT', '512M');

This seems to have solved the problem for now.

Logged in, saw that Wordpress and some plugins and themes needed to be updated, and updated them too. After updating, when I tried clicking on Edit for the home page, it seemed to work OK, probably because of the fix applied above.