The AI Copilot does not work 100% of the time on all aircraft at all times, especially for many 3rd party aircraft. It depends if the developer wants to support it. (They don’t have to support all MSFS functionality.) There are times when I try to use AI Copilot for taxiing where it just sits there and does nothing.
If the AI Copilot works on certain aircraft in FS2020, it (the workaround) should work the same on 2024 unless there are bugs in 2024 outside of the AI Copilot not in 2020.