Sims 4 constantly crashing

inmywonderland​  I'm so glad to hear that.  You can definitely test your old saves now if you want, although I'd move them alone to the new Sims 4 folder rather than restoring your old folder.  If you have any mods or custom content you'd like to use, test those first, also in the new folder, and remove or update anything that makes the game stop working.

Aside from that, you'll probably want to keep the contents of Tray, which holds saved households and builds, and possibly Screenshots and Recorded Videos.  The rest can be discarded.