Having once upon a time overfilled my oil by almost a quart, I think you are mostly right.

Engine oil should stay in the crankcase. During normal operation, some of it is pumped elsewhere to lubricate the crankshaft, cams, and other mechanical components. The rest of the oil sloshes and splashes around the crankcase keeping everything slippery. If there is too much excess in the crankcase, components moving can push the oil somewhere it shouldn’t be.

In my case, when turning left, the excess oil was pushed passed the piston rings and burned in a huge cloud of blue smoke. It wasn’t a proud moment, but stopping in a random service station and having Bruce try to drain a quart of oil out of the engine, because I couldn’t afford a full oil change was awkward.

… Anyway: all of that to say this:

If you have too little, your oil pressure light will probably come on. If you have too much, you’ll notice it somewhere else.