How to visualize data desktop projects after PWA retirement?

Bella-Puella -- If you want to stay in the Microsoft family of project management tools, you could use Project Server Subscription Edition (SE) and achieve the same results.  You would need to migrate the setup of your Project Online system to Project Server SE, as well as all the resources and projects in Project Online.  Your Power BI report authors would need to modify the report to connect to Project Server SE instead of Project Online.  There are also a number of PPM Partner organizations that offer their own "replacement" for Project Online as well.  So, you DO have some choices, but you will need to move away from your Project Online instance before September 30, 2026 to avoid losing all of your data.  Hope this helps.