RX560 graphics card

Hi, I've just bought a replacement Mac, transferred everything and it has an ATI Radion RX560 card installed. It had High Sierra OS and I updated it to the latest available . It won't wake up from sleep and I've done a search and there are many forums saying it is a bug in the latest update, but it can be sorted by using a program called KextUtility. I've downloaded it but can't see anything when I've installed it. I have no idea what it is. Then there is another forum saying you need to use WhateverGreen.kext and Lilu, again I have no idea what they are, what they do and how I should use them. Also that I need to uninstall SIP, which I think opens up my network to malware. I'm lost, do I wait for an update to the operating system for Apple to fix it (hoping it is imminent), do I purchase a different graphics card, do I throw the thing in the bin, do I wipe the disk and put El Capitan on? The whole episode seems to have been running for several months so I presume Apple are not too bothered sorting this?