Is it possible to detail a Semantic Model refresh?

Hi rbrandsbi,
Thanks for posting your query in community forum.

I understand that your Semantic Model's refresh time has been taking longer lately, and we get that you want to figure out why. Here are a few steps to help you diagnose and improve the refresh performance:

• If the network file sources have become slower due to connectivity or bandwidth issues, that could affect refresh time.

• Go to Power BI Service > Dataset Settings and check the refresh history for patterns in duration changes. Look for specific refreshes that took longer and compare them with past ones.

• Since your model is connected to Dataflows and network files, check whether the refresh time for these sources has also increased. In Power Query, use View Native Query to inspect the transformations applied to these sources. Check the Capacity Metrics App (for PPU) to see if there's increased load on the capacity.

• Even if DAX and ETL are minimally used, it's worth looking at the model to see if there are any unnecessary columns, tables, or complex calculations that could be simplified. Simplifying the model as much as possible will reduce refresh time

Alternatively, you can use incremental refresh, it reduces the refresh time because it can update only the changed data instead of refreshing the whole dataset every time. You can check this documentation below: 
Incremental refresh for semantic models and real-time data in Power BI - Power BI | Microsoft Learn

If this helps, then please Accept it as a solution and dropping a "Kudos" so other members can find it more easily.
Thank you.