Apples to oranges comparison. VS Code is a text editor whereas Xcode and Jetbrains are IDEs. The real comparison should be with Sublime Text vs VS Code. Sublime Text blows VSCode out of water while opening the same project folder.
Here's a naive comparison
~/workspace/iOS Project(develop)
time subl .
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Executed in 75.46 millis fish external
usr time 21.45 millis 106.00 micros 21.34 millis
sys time 14.84 millis 659.00 micros 14.18 millis
~/workspace/iOS Project(develop)
time code .
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Executed in 4.18 secs fish external
usr time 123.39 millis 99.00 micros 123.29 millis
sys time 175.07 millis 585.00 micros 174.49 millis
Here's a naive comparison