I created this workflow after testing out every native Slack - Notion integration out there. The native Notion one opens a clunky data input window, with parameters you have to enter every single time. I knew Relay.app would offer up a smoother experience, which prompted me to create this workflow.
At a glance this functionality may seem impossible because Slack message bodies are not available due to API limitations. Instead, I used the 'Get data input' action to create an easy input flow that feels in line with the rest of Slack's ecosystem.
By entering your chosen prompt (mine is #notiontask in this example), you can bring up a mini form for your task. Fill out the information you want, hit enter, and the task is directly saved to your Notion task database. Easy!