I get the same result with tf2.6 cpu version:

Epoch 2/25
352/352 [==============================] - 0s 1ms/step - loss: 0.3810 - accuracy: 0.8307 - val_loss: 0.4221 - val_accuracy: 0.7988

And also for tf2.5 cpu version it’s not getting slower anymore:

Epoch 2/25
352/352 [==============================] - 1s 2ms/step - loss: 0.3788 - accuracy: 0.8329 - val_loss: 0.4107 - val_accuracy: 0.8124

thank you very much!!