Afaik sending emails is much harder than receiving, because of several layers of anti-spam measurements, which don't apply for receiving (besides local spam filters).
Afaik sending emails is much harder than receiving, because of several layers of anti-spam measurements, which don't apply for receiving (besides local spam filters).
Yes, but send and receive paths don't have to be symmetric. It's perfectly fine to send via the third-party provider and receive to your own server and forward to the third-party provider.
The forwarding MX would need to support things like ARC and DKIM, though, or the forwarded emails themselves run a high risk of getting dropped as spam by the third-party provider.