Synfig Studio is described as 'Free and open-source 2D animation software for vector and bitmap artwork, featuring tweening, bone rigging, timeline editing, and advanced layer types across all major platforms' and is a very popular Animation Maker in the photos & graphics category. There are more than 50 alternatives to Synfig Studio for a variety of platforms, including Windows, Mac, Linux, Web-based and Android apps. The best Synfig Studio alternative is Krita, which is both free and Open Source. Other great apps like Synfig Studio are Animation Desk, OpenToonz, Glaxnimate and Pencil2D.
the learning curve for Synfig is too high unlike in Kage Studio, you simply draw, animate, and export.