Bud wont developing

It also does not help the lighting your useing looks to be old tech with massive LED's

I agree with everything numbers person said. I think it was caused by weak lighting in veg and only correcting now in flower that it had time to stretch up to it. Gotta raise and lower the light as the plant grows to adjust to its needs. Good Luck!

Those aquarium lights?

Any Auto I had problems with worked better under 12/1

I once had an issue with an auto that wouldn’t fully flower until I put it in 12/12

stretching is from genetics or weak light. Flushing won't do anythign but exacerbate whatever is going on when done blindly. Changing light schedule only matters if DLI is not where you want it. Whether you give 35-40 DLI over 12 hours 14 or 16 or 20 doesn't matter much, but some length of dark period is healthy for a plant. For an auto, 18/6 is fine.. if you want to do 12/12 that's fine too, as long as DLI stays they same you'll have a very, very similar yield and bud development. Recent growth looks to have a decent internode length, so the stretching is occuring lower on the plant from weak light. So i don't think more light at top will do much at this point. Vege growth shoulse cease soon, if that makes you feel better. Snap tallest branches horizontal a couple inches below the rest of the canopy. Support it. It'll heal in 24-48h and be stronger than before. At that point you need somethign to prevent it from bending upward again vs support.. so tie it down. The growth tip wil bend upward 2-4".