Hey man, what I would say is that have 3 inboxes per domain, and buy more domains if you need more inboxes. I would say at least have 10 email inboxes. supposing if you send 20 emails per domain that鈥檚 200 emails in a day. I think it鈥檚 a good infrastructure, and if you don鈥檛 want your messages to send into spam, start warming up your inboxes on instantly or any other provider you like. I think that鈥檚 a great way to land your email in the inbox directly.
It also really depends, at the end, on what you are offering to that person, what your subject is, and whether it鈥檚 very hookable or not for the icp you are reaching out to. I think it really depends on what kind of offer you are offering. I would really suggest you read some Alex Hormozzi tips for that like 100 million offer and 100 million leads. I think this pretty much sums it up, but if you can share your emails, I would try to help you out.
Try to email more people because the email reply ratio is 1-2% or even less than that, sometimes 0.5%. If you email a lot of people, like 100,000, then you鈥檒l get more replies.