Miro is described as 'A scalable tool for real-time and asynchronous team collaboration across devices with an infinite canvas, suitable for strategy planning and real-time feedback' and is a very popular Diagram Editor in the development category. There are more than 100 alternatives to Miro for a variety of platforms, including Web-based, SaaS, Windows, Mac and iPad apps. The best Miro alternative is draw.io, which is both free and Open Source. Other great apps like Miro are Excalidraw, AFFiNE, DeepNotes and Lucidchart.
Ideaflip is simpler to use that Miro, and feels creative and flexible in comparison