Worse than I thought
Having read the report compiled by the 'brave' team I was shocked by the extent to which commercial tracking and targeted advertising has ballooned in recent years. What applies to public sector websites must surely become an order of magnitude worse when commercial sites are considered.
For many years I have used Mozilla Firefox together with a set of seemingly reliable tracker, ad, and script blockers, on (Linux) PCs and Android devices. Visually they make visiting websites more tolerable. I was aware of an invisible underbelly of intrusive, possibly malignant, activity associated with sites; it suffices merely to use the NoScript add-on to obtain a list of intruders. Other blockers used in tandem reveal many more. Unknown is the number not trapped in that manner. Blockers and advertising malware creators presumably engage in constant battles.
Problems with social media sites, especially Facebook and Twatter, are well documented. However, not wishing to associate with morons I have no such accounts. Google, particularly on mobile devices, is problematic. It resides at the core of bundled Android systems. To rid oneself entirely of its baleful influence one must root a device and install either the open source Android or something else; rooting is risky because device manufacturers make it difficult to do; also some useful software, e.g. Barclay's Bank account connector, refuses to run on rooted devices for very good security reasons.
Google has released some Android applications it is hard to do without these days (e.g. maps and navigation). The only apparent solution to quandary is to use not-rooted Android on phones and restrict its scope for intrusion so far as the system permits. Given that virtual keypads, and even physical keys, are too small to make typing anything other than brief text messages using Signal frustrating, it follows that for the most part phones are suitable only for passive browsing.
Fortunately, VPN (hosted beyond '5 eyes' easy reach) is quite cheap and there is a reliable Tor application for Android. Even with this and all other mentioned precautions in place there appears to be little room for complacency.