It sounds like Segmented Calculated Metrics will solve for this! Here's
the documentation that will help with the process and flow...
https://experienceleague.adobe.com/docs/analytics/components/calculated-metrics/calcmetric-workflow/metrics-with-segments.html?lang=en
I would create this in two parts: First, create a Segmented Calculated
Metric using the "Visits" metric and a hit-scoped segment with Orders
Exists as the inclusion criteria. Name this Segmented Calculated Metric
"Visits with Order...