Tries to crank but does not, just a clunk from the starter

That single loud clunk you are hearing is the solenoid on the starter. It performs a mechanical function and an electrical function. Since you replaced the starter, with that solenoid on it, and the battery, that leaves the battery cables as the main suspects. Use a test light or digital voltmeter to measure the voltage going to the starter while a helper turns the ignition switch to "crank". Put one probe right on an unpainted, rust-free point on the engine block, and the other probe on the larger of the two studs on the starter, (not the cable terminal attached to that stud). You will find twelve volts there. What happens to that voltage when your helper turns the ignition switch to "crank"?

A professional would never order a new or used starter before doing the quick voltage check I mentioned. You can use a test light too, but to not do the test is like prescribing blood pressure medication when you do not have a blood pressure tester.

You might get an idea by turning on the head lights, then watching their brightness when you try to crank the engine. The problem with this is GM used to tap off the starter terminal, simply as a convenient tie point, with all their other circuits, including lights. A bad battery cable would cause the lights to dim badly during cranking. I am pretty sure on a car as new as yours, they do not do that, but I am not sure. If they do not, with a bad cable, the lights will stay bright during the attempted cranking.

If you do not have a helper to turn the ignition switch, you can do exactly the same thing with a screwdriver. When you are ready to take the voltage reading, use the screwdriver to connect that large starter terminal to the smaller one right next to it. That will make the starter spin and crank the engine.

If you do not have a digital voltmeter, Harbor Freight Tools has a perfectly fine one for under ten bucks. It often goes on sale for five dollars.

Nope; don't assume anything. This is the huge problem too with testing starters off the engine at an auto parts store. Due to their design, electric motors draw higher and higher current as they are loaded down. That's why a jammed motor that is not shorted will blow a fuse. When you force a starter motor to spin the engine, it is under its highest load and will be trying to draw its highest current. That is when defects in the circuit present a symptom. On a test bench, there is no load, so the motor draws very little current. A defect, like a loose or corroded cable connection, may not be bad enough to cause a symptom, so you'll falsely think it's working okay.

Try turning the engine by hand or with a socket and ratchet. It shouldn't take a real lot of effort to do that.

Put a battery charger on it at a slow rate for an hour. After that, measure its voltage with a digital voltmeter and tell me what you find.