my overall feeling on my own (slow) PC is that VSCode is faster on load (or, to be exact, I perceive it be to be faster) and provides a few features that I don't have on emacs.
You're right: once VSCode is in memory I think it uses more of it. But that's barely nothing when compared to rust-analyzer (which emacs LSP uses too).
I’m sure vscode would chew through resources during a heavy session, have you benchmarked more than just the startup of the application?