Issue
On some MacBook models, macOS may detect a 2560×1440 monitor connected through the ACT AC7922 as a 4K display. As a result, macOS may only offer refresh rates up to 60Hz, even though both the monitor and the AC7922 support higher refresh rates.
Cause
This behavior is related to how macOS interprets the monitor's EDID information and selects the display timing. It is not caused by a hardware limitation of the AC7922.
Solution
Manually set the display output timing to 2560×1440 instead of 4K. This can be done using tools such as BetterDisplay.
After forcing the native 2560×1440 output resolution, higher refresh rates such as 144Hz should become available in the macOS display settings.
Conclusion
If a MacBook only offers 60Hz when connected to a 2560×1440 monitor through the AC7922, this is typically caused by a macOS EDID/timing interpretation issue. The AC7922 itself does not impose a 60Hz limitation and is capable of supporting 2560×1440 at 144Hz when the correct output timing is selected.