You may be able to do something using Android’s internal Google Healthkit API and a free fitbit account. I used it to populate my weight from Beeminder to MyFitnessPal and Google Fit as described in this thread.
If S Health will sync to Google Fit, you can use one of the integrations on beemind.me to get your steps from Google Fit to beeminder. This might be what you’re looking for, and it’s what I currently use on my old Nexus 5X.