Re: Sims 4 origin dlc not working with steam base game
@Caitlinxzz Can you download the packs through Origin? Open your game library, click on the Sims 4 icon (probably the one with the Steam logo on it), select More > Expansion Packs, and click the Download button for any pack you own. Repeat for More > Game Packs and Stuff Packs.
Origin is using excessive CPU resources for a number of people these days, which could cause lag and other performance issues. The workaround is to put Origin in offline mode.