The latest benchmark I could find is 2022 and it's nowhere as bad as you claim
https://github.com/microsoft/vscode/issues/161622#issuecomme...
https://news.ycombinator.com/item?id=45253927
https://news.ycombinator.com/item?id=45254054
I know as a matter of fact that bad extensions slow down VSCode significantly.
https://news.ycombinator.com/item?id=45253927
https://news.ycombinator.com/item?id=45254054