Data Studio from Google is free, scalable up to as many dashboards as you can design, simple to use, and gives you the ability to gang data together from multiple sources all at once. Google Analytics, and Data Studio work great together. Since GA is free, it provides a great basis. If you are developing an App (mobile), then Firebase also is free, from Google, does a different yet slightly more app-mobile fovused analytics experience, and also is importable into Data Studio as a data source. Data Studio also queries BigQuery directly . Let me know if you need more info or have questions.
Best,
Chris