Learn English – An idiomatic alternative to “familiar with the matter”

"Treading" sounds odd because "to tread on" implies intentional stomping which isn't as comic/funny. In English I think we'd just say "They keep stepping on the same rake."

Other idiomatic images might be "They keep shooting themselves in the foot." or "...walking into the same wall."

Or for failed political systems one might say "Building castles out of sand."

More common is to simply say "Some fools never learn."

Also, the quote is actually: "Insanity is doing the same thing over and over and expecting a different result."

In (British) English, a painlessly idiomatic usage would be

Mechanic: Do you want to repair your car?

You: Yes, but please don’t go overboard.

As thefreedictionary points out, ‘go overboard’ literally means falling out of a boat, but idiomatically one can also go overboard on a task: ‘to do too much; to be extravagant’.

That can mean a range of things, from taking a task in general more seriously than it could possibly merit, to polishing thousands of tiny details that no-one could possibly ever see.

In the case of your example, the not going overboard scenario would involve the mechanic simply fixing the essential problem efficiently, and stopping there.

John’s colleagues would understand each other perfectly if one of them were simply to say, ‘John is going overboard again.’ They might or might not try to stop him, but they would understand that John is expending unnecessary time and effort, as usual.