Printing and preparing Mapbox's good-quality visuals through Power BI can be an uphill task since reports are rendered poorly for export. The inbuilt export options available in Power BI, be it PDF or PowerPoint, mostly compromise on the resolution, thus yielding blurry or incomplete maps.
Maintain Quality with Workarounds:
High-Resolution Screenshots: Do not export directly; rather, use the Snipping Tool in Windows or the Screenshot Utility in Mac to capture the Mapbox visual on a high-resolution screen.
Mapbox Settings: To ensure a sharper display prior to export, increase the tile quality or zoom level in the Mapbox visualization settings.
Export from Power BI Service: Depending on the browser, exporting from Power BI Service may preserve better resolution than exporting from Power BI Desktop.
Third-party Tools: If printing is a must, consider embedding the Mapbox visual on PowerPoint or external reporting tools capable of high-quality image exports.
Since this is one of the engine outputs that is not optimized for detailed map visuals, Microsoft may make improvements in the future. Are you looking for a solution mainly for internal reports or client presentations