The only critical step in setting up Sims 3 is manually limiting in-game framerates. The game setting doesn't work, so you'll need to use an outside tool to protect your GPU from overworking and overheating. There are several tools available, including this one:
https://community.pcgamingwiki.com/files/file/84-d3doverrider/?changelog=32
It's quite old, but it is compatible with Windows 10 and modern graphics cards, and it works with Sims 3. Its advantage is that it allows you to enable vertical sync even when the Nvidia Control Panel v-sync setting doesn't work, as it often doesn't on dual-card laptops. Just a note: v-sync is a fullscreen mode setting, so if you'd prefer to play in windowed mode, you may need a different tool, for example RivaTuner Statistics Server, or MSI Afterburner if you already use it for other reasons.
Regardless of how you approach things, be sure to double-check that your in-game framerates are capped. Bring up the cheats console (crtl-shift-C) and enter "fps on" without quotes. A number will appear in the upper right corner of your screen, and it should never go above the refresh rate of your monitor.
As far as mods go, Sims 3 runs mostly fine without them for a little while, but if you want long-running saves, a few from NRaas are extremely useful. I'd never play without ErrorTrap, Overwatch, Traveler, and MasterController; the first three help without any player input, while MC does nothing unless you run a command. Register and Traffic are also helpful in addressing issues with role sims (including stray animals) and vehicles, respectively. There are plenty of other mods that can be useful, depending on your playstyle and which packs you have installed. But rather than list all the (very many) possibilities, it would be easier if you described what you hope to accomplish so people could make recommendations.
