Yes, the systems logic is identical in all of our aircraft in both MSFS 2020 and MSFS 2024.
In the RJ, pressing one of the FADEC fault/off buttons will turn OFF the respective FADEC unit. Pressing it a second time will turn ON the respective FADEC unit (after a short delay).
I have just tested this on my end in MSFS 2024, and it is working as above, so if you're seeing anything else, could I kindly ask you to raise a support ticket with Just Flight Support via the following link, and our support team will be able to assist with further troubleshooting: https://www.justflight.com/support
Mark - Just Flight