As a user of Litchi exclusively, I choose to remain blissfully unaware of all DJI firmware updates that are imposed on the unwary who still use DJI Go4. In addition to enjoying the superior performance of Litchi in comparison to DJI Go4...
Used Mavic 2's since 2019. The original controller you put your phone in is the RC1-A or RC1-B. The RM500 is the only 'smart' controller that will work with the mav 2. It has the built-in screen.
Try using a different cable to connect the drone's RC controller to the smart device ( Android or iPad). Sometimes using a different cable will restore the drone's connection so that normal flights can resume.
I have a few non-OEM Apple...