JRiver Media Center supports up to 32 channels of DSP for each audio device with crossovers, PEQ, Linkwitz Transform, custom routing, bass management, clip protection, Protect Mode (digital fuse), convolution etc. You can pretty much do whatever you want. I can even route 32 channels of decoded Dolby Atmos through it from an external source. I've been using JRiver for 17 years now.
I have three MOTU AVB interfaces, the RME AVB Tool and the RME M-32 DA Pro. I could play to them all simultaneously from JRiver if I wanted.
And for 59 dollars! I'm going to download the free trial and check it out. What you describe sounds amazing