API and the Gantt "Compare Baseline" date.

Is it possible to pull the date that is selected on a project Gantt’s “Compare Baseline” date into the API data?

The date I’m referring to can be found in a project Gantt > Gantt Options > Compare Baseline

I’m using Asana’s API for building dashboards in PowerBI.

No, sorry, this isn’t currently available via the API.

Is there a roadmap for this? Although the visualization via Gantt is nice, we need actual data in terms of project deviation from the baseline for each task and subtask (example: task A was 4 days more than the baseline).

Asana doesn’t generally share their roadmap, so we won’t know unless/until it’s implemented, or (in some cases) at least in the works.