I've had success using a lightning SD card reader on my iPhone 8+, however, if the SD card is PACKED with pictures, like 16GB or more, it will crash and not show any photos on the card.
What I do is open up the "Files" app on the iPhone, it's a native/OEM app that you don't need to download unless you deleted it. After that app is open, then I'll plug in the SD card reader and wait a minute and I'll see the folder pop up and I can then drill down into it and download/view photos. It's slow if you just view them, but I have an older phone
