Migrate 25 Mailboxes: Microsoft 365/GoDaddy → MXRoute (SPF/DKIM/DMARC incl.)

We've want to move ~25 mailboxes off Microsoft 365/GoDaddy hosted email to MXRoute (open to a strong alternative if you can justify it in your proposal). We're looking for a contractor who can deliver a clear execution plan and then run the migration to completion. Current environment: ~25 mailboxes on Microsoft 365 via GoDaddy, each under 5GB Mix of forwarding rules, distribution lists, aliases, and groups A third-party CRM depends on our current email deliverability (SPF/DKIM/DMARC) and must not break Users will keep Outlook desktop access — we are purchasing Office 2024 Professional Plus (perpetual license, not subscription) separately, so mail just needs to connect via IMAP/SMTP; you don't need to worry about M365 license provisioning What we need from you: A written migration plan and cutover timeline submitted at project kickoff (before any DNS changes go live), including a rollback plan Full migration of mail, forwarding rules, distribution lists, aliases, and groups to the new platform with zero data/email loss DNS cutover: MX, SPF, DKIM, DMARC — coordinated so our CRM's deliverability is not disrupted A cutover approach that minimizes business disruption (e.g., staged/parallel mail flow, off-hours cutover, clear rollback trigger points) Post-migration validation and 1–2 weeks of monitoring for spam/phishing or deliverability issues Documentation of the final DNS/email configuration for our records Nice to have (bonus, not required for this scope): experience with Keycloak/SSO, LDAP integration, or email marketing platforms like Brevo, as we may extend this engagement into related infrastructure work. Timeline: We consider this a low-to-moderate effort project given the mailbox count/size and would like to move quickly. Please propose your own timeline in your bid. To apply, please include: Your recommended platform (MXRoute or alternative) and why A short outline of your migration/cutover approach Relevant experience with O365 migrations and SPF/DKIM/DMARC coordination for third-party deliverability Fixed price or hourly quote, with estimated hours/timeline Earliest start date