Some large enterprises use MDM to deploy certificates and proxy policies that essentially force you into a MitM situation, with the intention of tracking browser usage.
Location is a bit more tricky. I would say that's less common, but I've seen MDM solutions that offer location tracking as a feature
I'm speaking to what's possible to accomplish out of the box with G Suite's Advanced MDM offering, without an extreme amount of additional effort.
(This is relevant because, when prompted to install a MDM profile, the MDM provider such as G Suite is visible to the end user)
For an MDM solution on iOS there's a big list of supported profiles you can deploy after the MDM profile is installed ( see https://developer.apple.com/business/documentation/MDM-Proto... under "request types").
If the device belongs to the organization, you might not even know these profiles are installed, if it's a BYOD environment you know you are installing the MDM profile and if you open the settings page you can manually inspect which other sub-profiles have been installed by the MDM.
But you're right the MitM itself isn't built into the MDM, because that's a totally different product category ("Secure Web Gateway"). The MitM setup only works if you have an MDM to enforce the certificates and proxy setup upon the user.
For g suite location is under Mobile management. They list it as a find my phone type of feature. There's even a picture of it on their marketing.
Unless I'm missing something, there's not an obvious way to "spy" on employees, which this article is claiming. Perhaps it's possible, but if it is, it would require a lot of deliberate effort to accomplish. For example, there's not an out of the box way to track employee location. There's not a way to track employee internet browsing history out of the box.
TLDR: using G Suite Advanced MDM, there are not out of the box solutions for tracking or spying on employees in the ways suggested in the article. It might be technically possible, but to accomplish it, your company would need to make a (large) deliberate effort to do this.