Hey! I'm drawing this visual effect idea, about 2D Portals!
I start with FBF (frame-by-frame) sketch animation in Procreate or Adobe Animate, then use Photoshop for some effects or shadows (but that's in the final process), and finally export it to Unity 3D. I use the animations as a Spritesheet In the engine and I mix it with some particle system. Sometimes, if I'm going to work in Universal Render Pipeline I use a shader for the Glow.