Barking at people on walks

I have a 5 month Aussi Doodle and need some help with barking.

When he was younger(literally last month…), he never barked at people on walks; he would gladly greet anyone with caution.

Now, I can't get him to focus on me and not bark at people. I try hard to correct him and pull his attention, but he is fixed till i pull him away or they are far enough away.

The only thing I can think of that changed was that he started going to a Dog Daycare, but only on the days my husband travels for work(aka no one home to watch him during the day).

I want my sweet dog back, not the big puppy that scares everyone.