if you're looking for something lighter than loopback, i loved soundflower which is the open sourced backend of loopback... https://github.com/mattingalls/Soundflower
and if you are on a arm mac there is blackhole
Discussion
Voice meeter is a decent windows option.
voice meeter works, Jack audio is a bit heavier than soundflower/black hole but works similarly to them, on windows & linux
I use jack for my bitwig stuff.
I’ve used it with vcv rack before, trying to make it as modular as possible. Vcv rack 2 allows for more ins and outs now, but I still like the hacky feel of running soundflower Jack and an audio device at the same time.