If you still have access to a working Mackie C4 controller (or C4 Pro), do you know about this remote script on GitHub? https://github.com/markusschloesser/MackieC4_P3
The remote script works in Live 12 and operates in 4 modes; Track-Device, Track-Channel-Strip, Song-Function, and User mode. The remote script doesn't implement any User mode functionality, or didn't until recently. Now, (a branch of) that MackieC4_P3 repo implements an interface with this Max sequencer project on GitHub: https://github.com/BilldarBagdar/C4Devi ... pSequencer. You can run the sequencer with just a M4L license. You only need a full Max license to open Max directly instead of via some M4L device in Live. Once Max is open, however you opened it, you can open and run the sequencer project (patches).
This YT video demos the sequencer running "in" Live 12 as the remote script's User mode, although you only see the remote script's "display" on the C4 for a few seconds at the beginning and end of the video (Song-Function and Track-Channel-Strip mode displays). Most of the video shows the sequencer's (the remote script's User mode) "display" on the C4. https://www.youtube.com/watch?v=rdjTxElN2JQ
Any other C4 users out there with Live and M4L?