Sometimes it also the availability of commands depends on the cable/adapter used.
If I connect my monitor directly via HDMI to my laptop I can send all the DDC commands I want, but when I use an USB-C -> DisplayPort cable ddcutil couldn't event detect the monitor. Sadly I must use this cable, because it's the only way I can get 4K@60FPS.
Probably that cable contains a set of EDID chips to fool your laptop and the monitor - and as EDID works over DDC, obviously no DDC commands will pass.
I connected a Raspberry Pi I keep under the desk as a server via HDMI and I could easily issue commands. Wanted to write a deamon that translates MQTT -> DDC, but never got to that and I removed the cable last time i needed it for something else.