I'm curious if you have tried VSCode? It seems significantly faster than Atom and is built on Electron (and I think an Atom base).
The difference in responsiveness between the two editors is stark and it's a primary reason I never use Atom anymore (though the increasingly sophisticated intellisense and integrated CLI tools is what's kept me in VSCode).
There are a few things I like about Atom that keep me from switching despite its speed.
I just wish it was native, or at least a little faster. It's got bugs, too.