2021 Forte GT w/GT2, Currant Red, Wagner-Tuning Intercooler, Evilla Exhaust, Takeda S1 Intake
Your current 2.0L engine's fuel system is controlled by the MAP sensor. The 2020 2.0L engines' fuel systems are controlled by a MAF sensor. There is NO WAY your ECM will work with the 2020 engine!
Another problem you'd run into if you were to try to use the 2020 ECM is that the Transmission TCM is integrated with the ECM and since you don't have a IVT transmission it wouldn't function properly.