It's prolly Red Melon's 2nd cmv:
https://youtu.be/dlOdcyRT3KA?t=87That is prolly the combo he is talking about. I have not tested it extensively, but I'd expect it only works out of 22B, or from something like a 5C counter hit 22B. It is not really a matter of speed, but actuate timing to link the 22Cs. The timing requires that you buffer the 22 input during recovery, and hit the C on, or possibly a few frames after, the 1st frame of recovery. The buffer window for the 22 input is flexible, 8 frames, but the button press needs to be after recovery is complete, but also in the 8 frame buffer window with the motion.
The short answer is that it's hard for new players to gauge the timing, because the animations are fast and not always obvious. You are indeed, prolly inputting it too late. Do the 22 during the recovery, then time the C for frame 1 of recovery. To me it feels like 1-2 frame link, but I have not tested that. I'm too lazy to record it and go frame by frame.
It also appears to work on everyone. No, I did not test every char, but a few: Arc, Aoko, Ries, Warc, Wara, NAC, Len, VShi. Enough of the weird and more normal ones that I think it's universal.
Hope this helps.
-TexasTim-