It’s very strange, normally the error logs should be displayed on the page.
Fortunately, there are some other parameters to tweak, specifically WP_DEBUG_DISPLAY and WP_DEBUG_LOG. I tried enabling both on your website and still nothing was visible on the page. But it did create a file in wp-content/debug.log, with the message:
[02-Feb-2023 18:36:34 UTC] PHP Fatal error: require_once(): Failed opening required '/XXX/wp-admin/includes/upgrade.php' (include_path='.:/usr/share/pear/') in /XXX/wp-admin/upgrade.php on line 22
So it does look like some files are missing from your site. Please add the missing files, preferrably through the method described in How to fix a corrupted WordPress installation.