Natron is essentially the FOSS version of Nuke. And Nuke may seem overkill, but using it for simple tasks at first is a great way to familiarize yourself with the tool before using it for more complex ones.

I used to use Nuke just to do some colour grading, or composite two animations together, back when I was in school for 3D animation. "Simple" stuff that Blender could've handled, but I liked how Nuke was designed specifically for composition and VFX. The focus helps, I find. Which made me happy that Natron is a thing (although I recall it having some stability issues with me).