Using Direct Query my pbix is extremely slow

Hi MCacc 

1. The relational database source can be optimized in several ways, as described in the following bulleted list.

https://docs.microsoft.com/en-us/power-bi/guidance/directquery-model-guidance#optimize-data-source-performance 

2. A DirectQuery model can be optimized in many ways, as described in the following bulleted list

https://docs.microsoft.com/en-us/power-bi/guidance/directquery-model-guidance#optimize-model-design 

3. Optimize the report design:

https://docs.microsoft.com/en-us/power-bi/guidance/directquery-model-guidance#optimize-report-designs 

4. The benefits of Import and DirectQuery models can be combined into a single model by configuring the storage mode of the model tables. The table storage mode can be Import or DirectQuery, or both, known as Dual. When a model contains tables with different storage modes, it is known as a Composite model. For more information, see Use composite models in Power BI Desktop.

There are many functional and performance enhancements that can be achieved by converting a DirectQuery model to a Composite model. A Composite model can integrate more than one DirectQuery source, and it can also include aggregations. Aggregation tables can be added to DirectQuery tables to import a summarized representation of the table. They can achieve dramatic performance enhancements when visuals query higher-level aggregates. For more information, see Aggregations in Power BI Desktop.

Alternative, you can use the performance analyzer to exam report element performance https://docs.microsoft.com/en-us/power-bi/desktop-performance-analyzer Or the dax studio: https://community.powerbi.com/t5/Desktop/VAR-and-FILTERS-combination-to-make-an-efficient-column/m-p/809831#M389380