Well, near zero resistance actually means the circuit is good, ie there is little resistance to those magic little electrons flowing. Imagine a water pipe with very little resistance to water flow so that's good. If you can't get a resistance measurement ie near infinite resistance then that's bad, the circuit path is blocked. Some multimeters have a circuit testing setting and beeps if the circuit you're testing is good with no or low resistance. That's pretty easy to use
It would be worth getting a 2nd opinion before diving in to change the CMPS. If there's a problem with the 5v supply or earth then you'd be wasting your time and the fact you have MAP sensor fault codes coming up too then it looks more like a circuit problem than a component failure but it could even be the MAP sensor itself throwing everything out and dragging the CMPS down with it
So you really need to have both MAP and CMPS circuits checked for continuity and then checked for 5v and earth supply. If you've got that then you need to check the earth shield wire and then check the signals from both sensors. Really not difficult for a decent electrician but it might be worth finding a good one to check it out for you
If you need to, then you get to the camshaft sensor itself from the top, it's just the connector that is half way down the engine front