High Inbox SMTP Server Setup

I need a production-ready SMTP server that can reliably push 3,000+ messages every day while keeping at least 90 % of them in the primary inbox, not the spam folder. The environment must be properly authenticated with DKIM, SPF, and DMARC, and every connection secured over SSL/TLS... (Budget: $30 - $250 USD, Jobs: DNS, Documentation, Linux, Postfix, SMTP, System Admin, Ubuntu, VPS)