Any ‘tips’ to help dog stop shadow/light chasing?

My Cockapoo 2 years old has developed shadow/light chasing 6 months ago.

It’s only been 3 weeks since I really pushed hard to prevent him shadow/light chasing

• I put up blackout blinds as we have high sunlight in back of our house

• Anytime I see him starting to shadow/light chase I will clap my hands or “uh!” Command and move him along

• I will walk him morning for hour and afternoon for hour (play ball in park if weather permits)

• Hide treats in kong toys to play

• interact with him daily playing ball, doing tricks

He is showing improvements and feel I have 70-80% of my doggy back! But he still has that ‘urge’ to shadow/light chase even if there’s no light or shadow in the area!! It’s disheartening to see each time, I am probably over sensitive to it

He sometimes grabs a toy and lays down eyes darting left and right to things not there? So I will shoo him off but he will Godo elsewhere within seconds before I shoo again and he may be good or relocate

Worst days is the really sunny days Best days overcast

Night time coming slight problem from lights in house but only certain lights affect/trigger him??

Anyways

Any extra tips or suggestions to help train him out these habits?

I know a vet behaviorist is an option but medication along with what I am already doing?