And realize that if you're distrustful of the cable, you should be even more distrustful of that gadget which has even more space to add malicious parts and you're still unable to check it.
The normal PortaPow tells the device that it's a charger.
The extra paranoid version with no components on the board will often limit charging, it depends on how the device treats a complete lack of data pins.
Not exactly. You now have to trust one entity instead of many, and it's an extremely small chip that can't do much, and the hack would have to be built in at purchase time, and the hack would have to take over your phone to exfiltrate.
But if you're worried then get one that has a resistor and only a resistor.
It depends on what kind of attack you're trying to block.
If you want to block attacks that use the external data pins, then a USB condom will keep you safe. Regardless of whether it has a chip in it.
If you want to block standalone attacks from a malicious cable, then a USB condom wasn't going to help in the first place. For standalone attacks in particular, the risk from a chip-having condom is similar to the risk from a cable, but a cable can use bigger and scarier chips than the one in the PortaPow.
e.g https://www.amazon.com.au/s?k=PortaPow