@Faerielle Your screenshots look mostly normal, although you should see a little improvement by increasing the in-game resolution. Right now, you're playing at 1280x1024, but you could instead try playing at 2560x1440 or another resolution with a 16:9 aspect ratio. You might need to quit to desktop and reload the game to see the full benefits.
Unfortunately, Sims 3 tends to look less than crisp in general while in live mode. If this continues to bother you, try looking into some HQ (high quality) mods, which are generally not actually mods but edited graphicsrules.sgr files (or suggestions for your own edits). The directions typically only list where to add the file on a Windows PC; you can find them here in macOS:
[install location] > The Sims 3.app > Contents > Resources > The Sims 3.app > Contents > Resources
The install location is likely either Applications or Users > your username > Applications. When you're looking at an .app, right-click on it and select Show Package Contents.