I have found in this post a workaround to this issue:
https://forums.developer.nvidia.com/t/official-tensorflow-for-jetson-nano/71770/127
It looks like the current Tensorflow for JP 4.4 was compiled with --config=v1 flag., as V2 behaviour seems to be disabled in default.
The workaround is:
import tensorflow.compat.v2 as tf
import tensorflow.compat.v2.keras as keras
tf.enable_v2_behavior()