What do you mean by open and closed? ChromeOS is based on ChromiumOS, which is open source. I guess macOS is based on Darwin technically, but the ratio of open source to proprietary is much higher for ChromeOS than macOS, no?
Well, then you can only put it in dev mode and use chromebrew. Which I am glad exists, but even installing node can be a pain and the way to get it running changed over the years.