B2B Bulk Email Deliverability Setup

I’m looking for a full-stack solution that lets me send large volumes of B2B emails and have them reach the primary inbox—not spam or promotions. I don’t mind switching platforms or adding new infrastructure; what matters is measurable, repeatable inbox placement for every campaign... (Budget: $30 - $250 USD, Jobs: B2B Marketing, Bulk Marketing, Email Campaign, Email Handling, Email Marketing, Interspire, SendGrid, SMTP)