The default schedule is every second, as you can see in this core file below.
<!-- /app/code/Magento/MessageQueue/etc/crontab.xml -->
<job name="consumers_runner" instance="Magento\MessageQueue\Model\Cron\ConsumersRunner" method="run">
<schedule>* * * * *</schedule>
Re-running cron restarts the consumer.
If you are having issues with the indexes cron execution and your server is CPU optimized, yes you can use a separate process for it.
use_separate_process | Run this crongroup’s jobs in a separate PHP process
Reference: Specifying Cron group options