WetGeek As I said, I have much to do now. I'll refine my experiments later, but if you want all sortts of distros and DEs compared, I invite you to participate in the research.
I don't need to research, and neither do you, because I can look at the system requirements for various lightweight distros and can reach a reasonable conclusion about how they will stack up against Budgie, Gnome, MATE and Plasma running on the stated specifications.
Of the lightweight distos I mentioned:
Bohdi -- 500MHz processor, 128MB RAM
Linux Lite -- 700MHz processor, 512MB RAM
Lubuntu -- Pentium 4 processor, 512MB RAM
Puppy Linux -- 333MHz processor, 256MB RAM
MATE, by the way, is generally considered a "middleweight" distro, falling somewhere between the heavyweights and the lightweights. I'm not surprised that MATE and Plasma perform similarly, because I never gave a thought to either, but to me that means that both fall somewhere between heavyweight and lightweight. Budgie is usually considered a "middleweight" as well. Gnome is considered, as far as I know, a heavyweight by all and sundry.
Getting back to the thread, the real question is whether any of the Solus DE's will work well on @pLaYeR45's 2GB RAM laptop. I thought MATE might be fine in that environment, but it doesn't look like it will perform any better than Plasma. He might be better off using one of the lightweights, or perhaps Zorin 16 Lite (XFCE) which has similar requirements (1 GHz processor, 1GB RAM).
Solus Budgie is going to quickly toss the laptop into swap land:
Solus Budgie running idle (only Screenshot open):
Solus Budgie running browser with 4 tabs open (with screenshot open):
To my mind, that tells the story. I don't know if Plasma or MATE will work better on 2GB, bare metal. VM's are somewhat deceptive when measuring baseline CPU/RAM use because a good bit of the processor use happens at the host level.