Look, I'm not super paranoid. Really, I'm not. But there are three things that I make sure I do when I'm out and about. I seek out the best coffee I can find. I make sure I use a VPN when using public Wi-Fi, and I always make sure I use a USB data blocker, otherwise known as a USB condom
There is a number out there, but the brand I trust is PortaPow (because I've tested them and taken them apart to see how they work). PortaPow's 3rd-gen USB data blocker blocks all data transfer, but the built-in chip detects the type of device which is connected and swaps between Apple, Universal, and Samsung charging specifications, thus enabling the fastest charge possible.
And, for the ultra-paranoid, "="" data="" blocker"=""> that contains no electronics at all other than a wire bridge for the power and even has a see-through case so you can be sure no shenanigans are going on.