I would never recommend Windows or MacOS to anyone for similar reasons so those are not a comparison I care about either. I would certainly recommend a Chromebook over either if someone absolutely has no choice but those three, but there are almost always other choices if you make some time to teach someone.
Most Linux distros are a security shit show so pre-installed linux machines are hard to recommend to anyone that does anything high risk on their machines like financial work or journalism.
Degoogled ChromiumOS feels like a good security/privacy balance for most people but that is not currently a user friendly option for installation and upgrades.
In practice I find myself using and teaching others using their machines for anything remotely privacy or security sensitive to install and use QubesOS. For all the excellent privacy and security design it has a high learning curve and strict hardware requirements making it untenable for low-budget or low-tech users.