A couple of other things...
1. Check how complex your spines are; artists love to go overboard with the cool stuff spine can do! But the more complex the Spine the slower it will be to render. When first integrating it into our libs, I asked for a very basic test spine that just had it moving from side to side, to compare performance Vs animation frames. Turns out this basic shape still accidentally contained a totally unneeded mesh!
2. Pixi v5 is able to batch meshes, so (taking a wild guess you're making a slot game!) if you have multiple of the same symbol spin through, v5 can batch those for faster rendering time when v4 can't.
We have just released RevoltFX - a framework to create stunning particle effects.
You can create particle emitters and time based effect sequences and nest them all together.
Check out some samples https://samples.revoltfx.electronauts.net/
Get the library on Github https://github.com/bma73/revolt-fx
To create your own effects use the RevoltFX online editor https://editor.revoltfx.electronauts.net/
Get the editor on Github https://github.com/bma73/revolt-fx-editor