Sounds like you are doing everything right
My last dog, Tina Whippet, came to us at 16 months old and hadn't had a bit of training.....gosh, she WAS loopy!!!! I took her right back to 8-week-old puppy training and made sure my pockets were ALWAYS full of tasty treats like cooked sausage (chopped up), smoked ham and tiny dog treats. I had her on a 20ft line so she could mooch about on walks and enjoy sniffing everywhere and rolling in the grass etc but every now and then I would call ''Tiiiina, Here'' with a happy voice and arms open wide and she would, after a day or two, turn on a sixpence and come sprinting back to me
I made sure she was 200% at her recall before I risked letting her off and took her to Silver Sands beach which is an enclosed beach with high cliffs around so no distractions (other than gulls on the tideline) and we had a fantastic game session interspersed with my calling here and rewarding her every time with a treat
Sometimes I would call her even if she was 6ft from me, not just the full 20ft, and EVERY time it was a game....lots of treats and a BIG hug from Mummy
Within a month she was 99% reliable....the only time she wasn't was if she saw children on the beach and wanted to run up to them and play (she came from an old lady who had grandchildren) so I made sure I was always on the ball and knew what was up ahead
As you said in an earlier post it's all about repeat, repeat, repeat
Be consistent and I'm sure Enzo will soon be an absolute paragon of virtue
One other little thing that crossed my mind when reading the original post: could Enzo possibly be reaching the Terrible Teen phase? Even the best trained dog in the world will often start to ignore their owner once they reach 8+ months of age and the dreaded hormones start kicking in
It sounds like you are doing everything right though with the training so perhaps that was all he needed