Need Audio Drivers for iMac2017 after WindowsInstallation without Bootcamp

I have the following Problem:

I once installed windows via bootcamp. after some time my brother deleted mac os from my mac and i was left with only windows 10. Now I saw that my windows is installed on the hdd and i wanted to move it to the ssd for performance. I tried many things to preserve my original windows copy but eventually downloaded windows onto a drive, restarted the mac and held the alt-Key. Now i could install windows from my drive. The Problem are the drivers. I got most of my drivers back but i cant get audio drivers and bluetooth drivers to work. I tried downloading a bunch of drivers (CirrusAudioCS4208x64, CirrusAudioCS4206x64), bootcamp support software (that *surprisingly* did not work) but i cant get it to work. I am now deciding wether to try to get the right drivers or trying to delete the whole mac and download macos onto it (which i also have no idea how to). Is there anyone with ideas on what i could do?

Many Thanks in advance