Checkout chromium and try that on its tree. Or rgrep. Then try searching it with vscode and compare the timing especially with second and following searches. And vscode is smart enough to search files that where opened recently first bringing useful results instantly.
Of course if you need to cross reference the entirety of a gigaproject like Chromium you're going to need some sort of a cache and smart search. If I was a Chromium dev I'd probably set something up to help with that.
99.999% of source trees are a tiny fraction of that size however.
As I mentioned in another comment I routinely hack in the Linux kernel which contains about 15million SLOCs (per sloccount) and ripgrep takes less than 5s on a cold run and is near instant after that. ctags lookup almost instant regardless of cache. And that's on a 5 year old middle of the line SSD and CPU.
Inability to easily deal with chromium-sized repositories out of the box might be a deal breaker for you but it's a total non-issue for me.
