Many of those map sites are reliant on crowdsourcing and whatever so if you notice an error you should fix it. Beyond that, I've found Google Maps to be the most reliable one whenever I need to travel or have a delivery shift. Even if it's not spot on I can at least look around with Street View and get a feel for things, or at least be in the general area and then use my incredible gift of free will and human thought to figure out that if it's telling me to turn down a street that I don't want to turn down that I probably shouldn't turn down it and either consult locals to get correct directions or just be a bit more aware of my surroundings and look. If you're concerned about fine details like "it told me to make a U-Turn to get into a parking lot even though I can see I can just make a left here" then my suggestion is to just do that.
If that's too much for you, buy a physical map as long as it's recent. Big cities will more than likely have highly detailed maps for you to purchase at local gas stations or tourist stops or wherever. Otherwise, there's not much better you can get.