FLoC Can Go FLoCK Off
You can optionally check if you're affected by this plague by going to the Electronic Frontier Foundation's Am I FLoCed.
Your first, and best option(!), is to simply switch to a proper, privacy respecting browser. Brave. for example, has promised to never implement this garbage, and seeing as its Chrome-/Chromium-based there's virtually no reason why not. Other alternatives include Vivaldi and Microshaft's Edge.
However, if you for whatever reason can't or don't want to switch from Chrome, then you should immediately block it by installing DuckDuckGo's privacy enhancing Chrome extension. It won't force you to use their search engine if you don't want to, and you still receive a ton of protections for your online privacy, including the new FLoC.
Also, no, getting yourself a VPN will not actually help mitigate this issue. Though, that won't stop us from being greedy bastards and try to trick you into believing it will anyway. Like this: Follow our totally-legit referral link to Random-Totally-Legit-VPN – the best VPN service that exclusively caters to gullible suckers that don't know the first thing about internet security or privacy! Try it out today by ordering the Premium 10 year package right now and get a whopping 95% OFF for only $69.99! Hurry up though, the offer will expire on 12-31-2021!
All website operators should follow GitHub and many others' decision, and preemptively add the opt-out header for Google's new shitty tracking proposal.