Sims 3 .dmg Package Includes Unusable 32-bit installer
@686e84fce082d055 That's very strange—the EA App isn't even supposed to offer the 32-bit version of Sims 3. (The App's minimum requirement is Catalina, which can't run 32-bit apps anyway; users of Mojave and earlier still run Origin.) And it's not a common problem—you're the first to report it on this site, including among those who don't have the 64-bit "entitlement" on their accounts in the first place.
Your issue may well be that missing 64-bit entitlement, so please go back to support and ask that it be added to your account. Feel free to link this master thread, which mentions expansions but is equally valid for the base game:
Perhaps an accepted solution from an EA community manager will help.
If you get the 64-bit entitlement added and the App still tries to download the 32-bit installer, please let me know. I can flag the issue, although it might be a few days before there's a response considering it's a long weekend in the U.S.
