1.Hi Sachin here im using STM32L4R9AI chip for our design but i am getting a issue like where the flash size is showing 63KB Actually the flash size is 2MB. . 2.It only connecting in Hot plug mode & not able to erase also .

[Tesla DeLorean]

Nobody here is familiar with your specific design or connectivity.

What's reporting 63KB ? STM32 Cube Programmer ?

The ST-LINK Utilities are old an deprecated, might not fully support STM32L4+ devices.