I am from Linz, last year’s european capital for culture. There are some great concerts put on by ann and pat.
I think Vienna is the big area for hardcore music. Every week some great bands perform their shows. Check out shows in the Arena Wien or Shelter
Austria has only 8 million people, so I think there aren't enough hc kids outside of Vienna. Another aspect is that straight edge isn't common in Austria.
Here are some hc bands from Austria (but they are very underground :D)
anchors X up
Worlds Between Us RIP
Alpha & Omega
Nothing Gold Can Stay
I also think there are too many metal fans here so the hc scene doesn’t have space to get bigger.