key distribution is not correct in bull redis cluster

Question

I have around 16 queues, which are being used for delayed jobs. Some queues are used multiple times, In a one-time slot, there are some queues which are being used around 50 times and the rest are 3 to 4 times.

Implementation examples:-

import Bull from 'bull';

const queue1 = new Bull('queue1', {
  prefix: '{1}'
});

....

const queue16 = new Bull('queue16', {
  prefix: '{16}'
});

I am using redis-lab as a scheduler, Have a look at key distribution per shard

Any solution how can I improve the above graph