@Thornwood-Hollow When you buy the Sims 4 base game on Steam, it supercedes the copy in Origin, and from then on Origin will direct you to Steam to install the game. I take it this Steam account is still linked to this Origin account? If not, that would explain why Steam isn't picking up your Origin content.
Uninstalling and reinstalling Steam might help with the issue, that is if you want to keep playing through Steam. While you're at it, clear Origin's cache and uninstall it "the hard way."
https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/
https://help.ea.com/en-us/help/origin/origin/manually-uninstalling-origin/
Restart your computer before installing both Steam and Origin. Once they're installed, download the Sims 4 base game from Steam, then see whether you can install your packs from either Steam or Origin.
@puzzlezaddict I have steam linked to Origin. But I refunded the Steam copy due to this all. Meaning I only own origin stuff. Preferably I'd only use Origin anyhow. But it won't let me play without having both Steam and Origin running. It also won't list my dlc on Steam, just Origin, and only lets me download the base game through Steam. Even though I no longer technically own it on steam.
@Thornwood-Hollow Then try clearing Origin's cache, as described in the link above. (Restart your computer afterwards.) If that doesn't help, you'll need to contact EA customer support and ask for help.
