Hey I’m super inexperienced in Blender and just created a simple 3D pulsating orb this week but I can’t figure out why in Blender it looks so glowing and vibrant, and when I export it, it becomes flat and cartoony.
The first thing is that it’s not advisable to export an animation in Blender to an ffmpeg video format. Just export it to a normal PNG format, and you’ll be able to composite them into a video later. This way, you have the raw data to build the video.
The second is, how did you build the orb? The thing is that you’re using Eevee as the render engine, and Eevee has lots of options that you have to turn on/off to get it right. Add to the fact that the orb has some things going on. I see a bit of transmission/alpha map, emissions, and probably volumetric, which add the complexity of the rendering.
If you just want something right out of the box without too much fiddling with the settings, try Cycles. Or try to switch between Eevee and Cycles back and forth to see what’s missing in Eevee.