Can't disable debug/backtrace on WordPress
If you have command-line access and wp-cli enabled (with the CiviCRM extension), you can run: wp civicrm disable-debug.

If you don't have command-line access, run the following SQL via PHPMyAdmin or similar:

UPDATE civicrm_setting SET value = 'i:0;' WHERE name = 'backtrace' OR name = 'debug_enabled';