Just letting the devs know the issue. I’ve given up on trying to figure it out. What I ended up doing was installing MX Linux 18.2 which had the drivers already installed. Wifi and Sound worked out of the box.
Here are some of the sites I remember trying (I tried more):
MX-Linux uses by default a newer kernel and also newer firmware than antiX.
If MX-Linux works out of the box, then it is quite possible that a kernel-ugrade and possibly installing the realtek firmware from MX could solve the problem on antiX.