So with my roundabout method I created two different automations and it got almost all the way there.
On Mac, I use Spark and manually create a new note in Bear. Bear automatically opens, I manually export as a markdown document to a folder I created. Hazel moves the folder and creates a draft in DRAFTS and then I manually send to agenda. (If you are reading this and have a better idea I am all ears.)
On iOS, I use Spark to export to Bear, Bear Opens, I use the sharesheet to execute a shortcut I created to export to DRAFTS in Markdown. Then I manually send to Agenda
In both cases, the end note in agenda, has the link back to the original email in spark.
I am open to other solutions.