The logic feels obvious. A tired dog is a calm dog, so a longer run or another game of fetch should help. For some adolescent dogs, it does the opposite.
The exercise trap
Fast, repetitive exercise like fetch or running can raise arousal rather than lower it. Your dog gets fitter, not calmer, and the zoomies keep coming despite a longer walk.
More of the same activity is not the same as more rest. An over-aroused dog needs a different kind of session, not a bigger dose of the one that is not working.
What settles rather than revs
Sniffing walks, at whatever pace your dog chooses. Following a nose does calming work that following a ball does not.
Food puzzles and scatter feeding, which slow your dog down while they work for the same meal.
Chewing, on a safe, appropriately sized item, for a settled 10 to 20 minutes rather than a burst of speed.
Short, deliberate settle practice on a mat, rewarded for staying calm rather than for moving.
Relaxation is trained as a behaviour in its own right, in short repeatable sets below threshold. It is not a side effect of tiredness.
A day that works
Morning: a shorter walk with plenty of sniffing time, rather than a long fast one.
Midday: a food puzzle or a scatter feed while you are busy with other things.
Evening: a chew on a mat, and a few minutes of settle practice before the house gets quiet.
Behaviour change is built from management plus reinforcement together, and a calmer day is built from variety, not from adding more of one activity.
Safety note
If your dog became restless suddenly, or has started flinching or growling when touched, book a veterinary examination first. Sudden behaviour change warrants a veterinary examination.
Today's version, in one line: swap one fetch session for a slow sniffing walk, and see what changes by evening.