I’d like to setup Email Routing for inbox.mydomain.com, while keeping my existing MX records for mydomain.com to Gmail.
During setup, Email Routing will force you to delete your existing MX records. However, it seems there’s a workaround where you delete the root MX records, then setup Email Routing for the subdomain, and then delete the new root MX records pointing to Cloudflare, replacing them with your original ones (see: https://community.cloudflare.com/t/use-cloudflare-email-routing-for-subdomain-only/754454)
Is this allowed by Cloudflare? It’s unclear if Email Routing just isn’t setup up for this use case out of the box, or if Cloudflare is trying to prevent this behavior and could potentially be a Terms of Use violation, so best not to attempt to do it all.