@Lybron thank you for your willingness to assist.
Taking a similar approach to the blog post, I was able to use node-red to get the integration working via a webhook:
Node Red Export:
[{"id":"d92725ad.fa81d8","type":"tab","label":"Health API","disabled":false,"info":""},{"id":"7370ab07.315e84","type":"ha-webhook","z":"d92725ad.fa81d8","name":"health","server":"e056fc93.5eff4","version":1,"outputs":1,"webhookId":"health","outputProperties":[{"property":"topic","propertyType":"msg","value":"","valueType":"triggerId"},{"property":"payload","propertyType":"msg","value":"","valueType":"data"}],"x":90,"y":140,"wires":[["e25ad690.522868"]]},{"id":"e25ad690.522868","type":"function","z":"d92725ad.fa81d8","name":"Parse POST","func":"metrics = {}\n\nfor (i=0; i<msg.payload.data.metrics.length; i++)\n{\n value = 0\n for (x=0; x<msg.payload.data.metrics[i].data.length; x++)\n {\n value = value + msg.payload.data.metrics[i].data[x].qty\n \n }\n metrics[msg.payload.data.metrics[i].name] = parseFloat(value).toFixed(0)\n}\n\nmsg.payload = metrics\n\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":270,"y":240,"wires":[["46ee9e56.64c05","2af3c20c.33404e"]]},{"id":"46ee9e56.64c05","type":"ha-entity","z":"d92725ad.fa81d8","name":"update Step Count","server":"e056fc93.5eff4","version":1,"debugenabled":false,"outputs":1,"entityType":"sensor","config":[{"property":"name","value":"step_count"},{"property":"device_class","value":""},{"property":"icon","value":""},{"property":"unit_of_measurement","value":"steps"}],"state":"payload.step_count","stateType":"msg","attributes":[],"resend":true,"outputLocation":"","outputLocationType":"none","inputOverride":"allow","outputOnStateChange":false,"outputPayload":"$entity().state ? \"on\": \"off\"","outputPayloadType":"jsonata","x":520,"y":240,"wires":[[]]},{"id":"2af3c20c.33404e","type":"ha-entity","z":"d92725ad.fa81d8","name":"update Water Intake","server":"e056fc93.5eff4","version":1,"debugenabled":false,"outputs":1,"entityType":"sensor","config":[{"property":"name","value":"water_intake"},{"property":"device_class","value":""},{"property":"icon","value":""},{"property":"unit_of_measurement","value":"Oz"}],"state":"payload.dietary_water","stateType":"msg","attributes":[],"resend":true,"outputLocation":"","outputLocationType":"none","inputOverride":"allow","outputOnStateChange":false,"outputPayload":"$entity().state ? \"on\": \"off\"","outputPayloadType":"jsonata","x":520,"y":300,"wires":[[]]},{"id":"e056fc93.5eff4","type":"server","name":"Home Assistant","version":1,"addon":true,"rejectUnauthorizedCerts":true,"ha_boolean":"y|yes|true|on|home|open","connectionDelay":true,"cacheJson":true}]
Results: