Make 2d Nebula you can put in your backgrounds.
This uses different textures nodes for a different type of Nebula
He motion tracks the head onto the table, I think he should of used a smaller paper, and a model that would hide the paper. If he used small tape with dots, they might of been easier to hide also. A little planning means less work later.
Plugins that make Reptopolgy easier
Here is a list of most of the better add ons. Notice decimate is the first one and is included with blender and simply reduces the amount of polys in the mesh. (Very useful)
Good reference of dinosaurs running.
Nice walk and roar, if you rig your lizard well, you can do this type of animation.
Blender has a benchmark page, and there are numbers all over the place, you can't tell what's a real benchmark.
These videos show people rendering using a 3070 etc., and you can see how long.
Blender is a powerful program and if you don't have a fast enough rig, you won't be able to do the things you really want to. Forget about simulations, or large scenes.
Get 32gigs of ram or more, (ddr5 ram just dropped in price), Get a VideoCard with 12gb of vram or more, get a large M.2 drive, and an 8 to 16core Processor.