Virtual Private Networks, or VPNs, are popular services for (supposedly) increasing your security and privacy on the internet. They are often marketed as all-encompassing security tools, and something that you absolutely need to keep hackers at bay. However, many of the selling points for VPNs are exaggerated or just outright
You’re thinking of a MitM proxy, and generally speaking what you described is not a risk when using public wifi.
There are two ways you can set up a MitM proxy:
The first option will result in prominent warnings in all modern browsers. If the sites in question implemented HSTS and the user has visited them before, the browser will outright refuse to load them.
The second option will result in even more prominent warnings that you have to go out of your way to bypass in all browsers. The only way it wouldn’t would be if one or more of the following is true: