Give Feedback on my cold outreach strategy

I am a fresher and just joined a saas agency as an sdr, and now my task is to get clients for our voice agent. But so far in the past 2 weeks I have sent around 300 mails, reply rate is around 3% but most of them are out of office automated replies.
I have been targeting real estate agencies in California, so sending mails mostly to the owners and vps of agencies that have around 1-50 employees or are self employed.

I am using sales navigator for finding out the leads, and then apollo extension to find out the emails, and using Instantly with 2 different domains and 2 mail addresses from each to send the outreach message, and then 2 more followups within a span of 10 days. And right now my initial template is like this-

Hey {{FirstName}},

Running a real estate agency means you're constantly between showings, client meetings, and negotiations - and when a new lead calls in the middle of all that, there's a good chance you're not picking up.
We built an AI that picks up your phone for you - speaks to the caller like a real person, finds out what they need, and books them straight into your calendar. You just get a text with the details.
Want to hear it handle a live call in real time?

I want to know if this is a good strategy to follow or am I missing something, because I thought I would be able to book atleast 2/3 meetings in the first 2 weeks. Do I need to check the deliverability issues of my mails, or verify the lead emails further? Need suggestions.