In my experience what made Flash special wasn't the SWF runtime but teh FLA as a single editable file that bundled timeline, vectors, and code so an artist could hand over an animation and a developer could open the same file and tweak frames without a full rebuild. To recreate that loop I built a pipeline where artists export PNG sequences from Adobe Animate, TexturePacker packs them into atlases, a small tool emits a JSON timeline with frames as {spriteIndex,durationMs,easing}, and an AssetPostprocessor in Unity or an import plugin in Godot hot-reloads that JSON into AnimationClips so timing can be nudged in-editor. I've found the practical tradeoff is bigger assets and more import complexity, so make your timeline format human-readable for sensible git diffs, keep per-animation metadata minimal for easier merges, and accept that you'll be debugging the importer at 2am while an artist asks for 'one frame faster' but iteration speed pays off.