Suggestions

Business Requirements and Budget are the main decisive factors in deciding the Cloud App.

 For this, we need to look at the Business Website, Outreach Goal, CTA expected, and Email Content. The email content needs to have variables as much as possible.  Sending the same content to most contacts will spoil the domain's reputation.  We may have to start with the low volume to see the reactions, and then we can slowly build up the volume.  We can also choose multiple domains and mailboxes to increase the daily volume.  There are many dynamic ways to increase the volume, and we need to be very dynamic as per the mail server’s reactions to our Cold Email Campaigns.

Some suggested top Cloud Apps: Reply, Apollo, Snov, and FreshSales

For the long and steady business growth, I would recommend Reply.  However, if you plan to buy verified and Segmented lists, you may try Apollo. Let us talk more about it.