I can easily open 20ish projects, but the experience is often still sort of sluggish.
Like, change a file outside of the editor, open it again, and it’ll sit there stuttering for a bit while it realizes the file is updated and it has to re-index.
It’s not the end of the world, but the experience there could be more fluid. Because you do this often (e.g. every time you switch a git branch)
I often have several simultaneous PyCharm projects open with separate completely introspected and navigable virtualenv's with lots of installed libraries, and also ongoing DataGrip, and at times CLion or IntelliJ sessions ... all the Jetbrains IDEs are performing quite well. At times running Docker as well. 32GB Macbook Pro M1.
I'd be interested in even lighter than VSCode IDE ;)