The Q-SYS sACN Mixer plugin by Paul Ricard has been floating around various forums for years. It worked great until v9.4 but broke in v9.5.
This plugin was fixed by Mike Matthews (https://developers.qsc.com/s/question/0D54X00008Beoo7SAB/95-appears-to-have-broken-using-components-inside-of-plugins) and Paul provided his blessing in that same thread to keep using it and tinkering with it.
I have confirmed this as working on v9.13.1 LTS, and I have posted it here so it's easier for me to share with others.
This version also makes one modification over the original - enabling input pins (thanks Reid Wall). I have bumped the version to v2.1.7 as it combines changes by both Mike and Reid. (Mike's on the forums was v2.1.6)
There are other, newer sACN plugins available these days, which you may choose to use instead of this older one: