This would be extremely helpful in building out automation that will allow us to rate shop more effectively. The field in ChannelAdvisor is called "Must Deliver By" in our ChannelAdvisor order management page. The field is named DeliverByDateUtc in the ChannelAdvisor API.
There is another idea related to this called Amazon Delivery By Date that will need a "Deliver By" field. The only difference with that idea is it idea calls for ShipStation to pull the date from Amazon directly instead of ChannelAdvisor. So, while different, these ideas should both share the same underlying "Deliver By" field.
That said, once the "Amazon Delivery By Date" idea is completed (it's current status is "Investigating") this idea should be easy to complete by mapping the new "Deliver By" field to the DeliverByDateUtc property in the ChannelAdvisor orders API.
I did some additional review, and it turns out the field for Amazon is already available. The idea Add Amazon Delivery By Date was completed in February 2022. This means the underlying structure is already there, so it is just a matter of mapping the data fed by ChannelAdvisor to ShipStation.
This would be incredibly helpful in so many ways, and it should be a fairly straightforward implementation. Please take a look when you can @Moderator-Davis.