I thought you couldn’t side load apps on new iDevices. Do you have an alternative if what you want isn’t in the app store?
Remember, what we're talking about is ILLEGAL in China.
I wouldn't use a phone or tablet. I'd use a small computer I constructed or purchased from a trusted private source, and software that I trusted, probably open source, since that's available without alerting the authorities.
Illegal activity in a totalitarian country is dangerous business, and not to be left to -any- commercial entity. IMO.
The side-loading of apps on jailbroken iOS devices is a major industry in China and is a major source of malware for these jailbroken iPhones and iPads. the XcodeGhost, a supposed faster and easier to download version of Apple's Xcode for writing iOS apps, came out of that grey market in China, which actually had malware built-in to add to all Apps it created. Over 4000 infected apps were created for these third-party App Stores using XcodeGhust, and a four or so of them even wound up in the Chinese Apple Store. It is not much of a problem in the rest of the world where such side-loading Apps are not as popular.
Most likely these VPN apps will be appearing in the non-official jailbroken channels in China, but I would be very suspicious of their provenance. . . and security. I would not be surprised if some of the third-party VPN apps were not probably created by the very government who is banning the apps to entrap those who would use them.