I have very promising and stable results with an M1 Macbook Pro. I tested on a bare-bones Mac Mini before springing for the MacBook pro.
There will be a few stumbles, and I still have a couple of plug-ins and scripts that have to be run in Rosetta, but I am happy and productive.
My only concern in your question comes from the statement that you use After Effects for editing. AE is an animation, motion graphics, visual effects, and compositing app designed to create shots. AE is not, never was, and is a terrible video editing app. You do that in Premiere Pro.
As far as which machine to buy and how to configure it, spend as much as you can afford without going into debt.
I've tested the two models Max and Ultra and both are beasts for After Effects with the latests AE version. Not sure if the Ultra model is far better than the Max model (I get a lot better results in FCPX when decoding or encoding ProRes files. Working on heavy vfx projects with EXR files AE is at least 3 to 4 times faster even on the Max model. Cinema 4D is also impressive on the new Mac Studio. The only problem as Rick says is that I use some third party plugins that are not Apple Silicon native so in some circumstances I have to work in AE using Rosetta emulation. Also it is impossible to get the fan make noise on the MacStudio, it looks like a really efficient machine.