Premium Inboxes claims that self-serve inbox setup works 98 times out of 100.

Premium Inboxes helps agencies, SDR teams, founders, and GTM organizations scale outbound with infrastructure they can actually rely on. Trusted by 2,000+ GTM teams and responsible for managing 600,000+ inboxes. What you get: ✓ Official Google Workspace & Microsoft 365 accounts ✓ Vetted US & EU domains only ✓ Free infrastructure audit ✓ Done-for-you setup & authentication ✓ Unlimited replacement inboxes ✓ Dedicated support ✓ Deliverability-first infrastructure More replies. More meetings. More pipeline. Less time managing infrastructure.