Send with multiple servers

Sure. By default MailWizz will use all your available servers for sending the campaign emails, depending on their availability and your settings. By default, it will try to rotate servers after 200 sent emails, but you can configure this from backend > settings > cron > Change Server At.
If you also set a hourly/daily/monthly quota on the servers, MailWizz will follow that and exclude servers that are over quota.
Please note that when running under pcntl, these all happen per each process you define.