Great to see the site back up. The new CASTER is a nice update from v1. These apps are much easier to use and provide more functionality than the free
Blackhole driver. I did a full review video of
GC Room here and it makes Core Audio work more like Windows Audio does natively, great for routing a loopback track into OBS.
There's also
Rogue Ameoba Loopback which will give you full control of routing audio as well.