You can train your self to not overthink as much and medical interventions can help if for example adhd is involved. It's about the ability to choose where to put your energy and what trains of thought you'd be better off just leaving and just throwing the ticket in the trash.

Now if it's overthinking or not is subjective. Does pursuing the line of reasoning in question distract you from more important things? Does it hurt you without leading anywhere? Has your exploration gone so far that you've lost perspective? Is the solution you have good enough and any further improvements you might find is not worth your time? Are you working on too little data so even if the reasoning and assumptions are good in the end it's still not much better than a guess?