Slow with lot of projects

Hi, I'm using Intellij Idea to develop Angular/Ionic applications and I have a monorepo structure that is a folder that include a lot of Angular or Ionic projects.

Example:

/monorepo

/monorepo/project

/monorepo/project1/src

/monorepo/project1/node_modules

/monorepo/project1/etc...

/monorepo/project2/src

/monorepo/project2/node_modules

/monorepo/project2/etc...

I have a lot of projects and I frequently need to switch between them so I usually open the folder /monorepo with Intellij but code completition is much slower than if I open only one project at time.
Is it possible to open all projects together and tell Intellij to consider only one subfolder at time and switch fastly between subfodlers?

Thanks in advance.

Regards.
Davide