My Android phone shows insufficient memory even after deleting all the apps on internal storage
32GB internal memory! I envy you!

Anyways, it might be because of the android is,  which is perhaps taking up too much space.

Moreover, built in apps like Google apps and chrome cannot be moved.

Lastly, if problem persists, take your phone to an authorized service centre and explain the issue. Be sure to take a backup before going there.