Found it after some digging. Apparently shift has removed the queue.php config where we had our queue connection configured because laravel adds a default one. That default uses a .env var to override it, so we had to set REDIS_QUEUE_CONNECTION=queue because in our database.php we had

        'queue' => [
            'host' => env('QUEUE_REDIS_HOST', '127.0.0.1'),
            'password' => env('QUEUE_REDIS_PASSWORD', null),
            'port' => env('QUEUE_REDIS_PORT', 6379),
            'database' => 0,
            'scheme' => env('QUEUE_REDIS_SCHEME', 'tcp'),
        ],

and in horizon.php

    'use' => 'queue',

It still remains unknown why jobs scheduled by laravel 11 were scheduled in the correct redis server and ran properly...