There are too many mechanics on this thread.
If you try several films through the camera is may increase the gaps between frames.
If you are using a J12 then some overlap is possible.
If the camera is very worn, then the drive gears may be damaged. And you may need to strip and repair, cannabil parts or bush
But the most frequent fault is that the clutch mechanism between the sprocket shaft drive and the film take up has not got the correct amount of friction, it is a slipping clutch, it needs to slip.
Never had one with too much overlap before all mine start about correct and then open up the gap as the take up spool fills. Makes filing negatives difficult.
How easy is it to rotate the spool forks with the camera shutter wound on? Is the force required the same in both directions?