WebStorm on monorepo not highlighting code and not copying code

Hello!

I've been using WebStorm for few years now, mostly with Angular projects and all went well. For the past year, I've been working at the company with a large monorepo project containing web components. I noticed that once I open the whole monorepo as a project in WebStorm, the indexing, code suggestions and completion, as well as syntax highlighting were ultra laggy or not working at all.

At the time, I was working on a 2019 Intel MacBook Pro with 16 gb ram so I thought okey, maybe this is a hardware limitation. So I simply opened only the directory from that monorepo that my team is working on, and it started to work just fine.

However, I just received a tough spec 2023 M2 Max MacBook Pro, with 32 gigs of ram so I thought - hey, now opening that monorepo should be no problem, right?

In fact, the indexing and searching is not a problem. Clicking on the methods or code parts to see references and source files also works fast. Sometimes the "Resolving reference" windows pops up for few seconds, but otherwise it seems okey. I excluded "dist", "node_modules" and "temp" folders from the project to not waste IDE resources on those, as I am not interested in them.

But as far as coloring the code works - it's not working at all. And without coloring, documentation on hovering over methods inside code also doesn't work at all. Sometimes it takes 10 minutes for a file to get colored, sometimes it's not happening at all. Sometimes I get half-colored files, like some methods inside single file are nicely documented, some doesn't. When the code is not highlighted, copying it doesn't work, only the `Copying...` window with a progress bar popsup.

And again, opening only my team's directory as a project fixes all issues and it's blazing fast.

As I mentioned above, I excluded what I could from the project, I tried to invalidate cache, even manually delete `.idea` directory from the project to force it refresh the changes. Nothing helps. I don't see any process running in the background either.

I left the WS open over night and the code coloring started working for the better part.  Newly added code was colored with a lag. However, after closing and reopening the WS - all went back to grey and now coloring is not working at all. I would probably have to leave it forever open.

Any thoughts on the above? Has anyone encountered this issue? Are we just forced to avoid working with monorepos on a premium IDE?

Below is a pic of how the copying looks like and how the code is not colored. 

btw. I am using One Dark Vivid Italic theme but switching to default Dark theme didn't solve the issue.