Power BI Refresh Optimisation

My existing Power BI report pulls several large tables from Microsoft Dynamics 365 Business Central through the standard API. The model works, but the scheduled refresh now fails with frequent time-outs; reliability is my biggest concern.

So far I have:
• enabled incremental refresh on the largest tables
• tuned a handful of queries
• experimented with splitting data into smaller API calls

None of these measures has eliminated the failure. I need an expert who can:
1. pinpoint the exact bottleneck within the current data model, gateway settings, or API calls
2. redesign the retrieval strategy so the report finishes every refresh window without timing out
3. leave me with a clean, documented PBIX (or dataflow) that follows best practice for query folding, partitioning, and Business Central API limits.

Acceptance criteria
• full refresh completes inside the existing gateway time-out threshold on two consecutive days
• incremental refresh completes in the background with no user intervention over a working week
• documentation summarises every change made and explains how to maintain the solution

If you have solved similar Business Central-to-Power BI refresh problems before, please mention the approach you used or share anonymised examples.