Yes, I would suggest ensuring that chords are quantized. I’ve logged an issue for us to consider display-quantizing chords in the score editor, however, that might not be desirable under all circumstances.
Re C4 vs C3 vs C5: I’ve written about this before (because people were complaining about Dorico not using C3). Unfortunately this is just an unfortunate quirk of history that music notation applications generally use C4, but Yamaha keyboards I think for many years (before music notation apps) used C3, and most DAWs, plugins and sample libraries use C3. I think at one point Roland used C5, but that wasn’t popular.
This has been requested before in Cubase and is in the feature request database