1) boot with verbose + debug 0x100 mode, post screenshot
2) google or use kext updater.app to download, many ways to do this, please put in a little effort
3) Make sure to repair permission and rebuild cache after
4) DSDT has nothing to do with what version of MacOS, but with BIOS version and configuration. The old kext I meant is for wifi (IO80211Family.kext) Did you read Hervé's guide?
Here's the link if you have not. Make sure to read the last post.