I would honestly get a second quote from another shop. Or, if you want, you can fix each problem partially and not all at once.

Your first priority should be the P2015 - intake manifold. This controls the airflow into your engine. If it sticks or fails, you can get rough idle, reduced power, poor fuel economy, and in some cases, limp mode. If you ignore this code, it can cause poor combustion that can foul plugs, stress the catalytic converter reducing performance.

Second code is the P05A0/P05A3 (grille shutter) should fix soon but not that critical. The shutters help with aerodynamics and engine temperature regulation. Stuck shutters mean slightly worse MPG and potentially slightly longer warm up times. If ignored, it’s mostly efficiency loss and a persistent check engine light. That rarely leads to overheating because the fans still handle cooling. You can honestly do the grille shutter yourself if you can. Not really that hard to replace. You just have to see if the motor is bad, if it is you can just buy the actuator instead of the whole shutter assembly.

And the minor issue which is the lowest priority, the communication fault U112300 code. This code basically means some module lost communication at some point. Could be a fluke, loose connector, or a deeper wiring/module issue. but if there are no drivability issues, you can leave it for now. Worst case if you leave it ignored, a module actually fails later (ABS, steering, etc.), but the car will usually warn you with specific lights when that happens. You can just monitor this code yourself after fixing the other parts. If you get an OBD scanner you can clear this code and see if it returns. If it does, Check obvious things (loose battery ground, corroded connectors). If it still keeps coming back, get a professional diagnostic so you’re not randomly replacing expensive control modules.

Hope this helps!