We used to use a tool called flump to rasterize flash animations for iOS games (I ended up writing our runtime and renderer in Unity and later SpriteKit to consume that data). I bet it wouldn’t be too hard to build an exporter from Flash (the program, now Animate) to this runtime if the features are fairly compatible.
Flump was a fantastic tool in the early mobile days when there wasn’t really anything else to create quality 2D animations. I also wrote a few Flump runtimes and have since written a few more runtimes utilizing the Export as Texture Atlas feature in Adobe Animate. If the goal is to just render the rasterized output from the exported texture atlas animations it should be pretty simple to create a converter.
