Every day my active calories are listed around 1600. Even if I actually did much more or much less than this per apple fitness app. Screenshots attached for a day I ran a marathon (2934 calories) and the day after (257 calories). Superset says my active calories were 1654 and 1639 respectively for those days.

I also included a screenshot of my active calories for the last month per superset. It is pretty much the same number every day regardless of my actual activity for the day