Freshdesk's SPF include costs 7 of your 10 DNS lookups. Mailgun's costs 5.
Add Google Workspace and that's 13: every SPF check on that domain returns permerror, and DKIM can hide it for months.
Flattening is the last fix I'd try. Counts per provider and the order I'd go in:
Cold email with no limits on mailboxes or seats. Everything in the UI is also an MCP tool for your AI.

