@Jeansoo Yes, I have the jagged shadow edges; I thought you were saying that the shadow rendering wasn't working properly or something. Other boundaries, like the beach in SV, are also less than smooth, but that seems true for a lot of people. I've always thought that it was unavoidable to some extent in TS3, but others may disagree or find ways around it.
I should note that my monitor's native resolution is 2880 x 1800, and I play in 1280 x 800 because I prefer the way it looks. I'm guessing your in-game resolution is also scaled to your monitor as well? Most of my other options are set the same as yours, except my reflections are "mirrors only" and high detail lots is 2 instead of 8.
I don't get the white objects much though (at least on this computer), and I think that's because of the difference in high detail lots. I've found that it doesn't really affect my play, especially if I only have one or two sims, and of course there are many fewer objects for the game to render at any one time. On my old computer, some objects would show up white or as stencils for a few seconds, especially the first time the camera was on that lot in that particular play session, so I always figured that it was the result of underpowered hardware.
If you want to see a few examples, I've posted some pics recently from the PC side. In the first link, the fourth pic in particular shows the jagged shadows very well, but like I said, I've always thought that's just how the game looked. The second link is mostly scenery.
https://forums.thesims.com/en_US/discussion/comment/16476522/#Comment_16476522
https://forums.thesims.com/en_US/discussion/comment/16482964/#Comment_16482964
For comparison's sake, this is from the same computer but before I Bootcamped. Check out the water line in particular.
https://forums.thesims.com/en_US/discussion/comment/16417004/#Comment_16417004