@amandav101 I take it after your most recent clean uninstall, you've installed the base game only, no packs? (If that's not the case, please do another clean uninstall and reinstall only the base game.) Please also run the Super Patch again, if you haven't since this latest install. Running it later will undo the .sgr edits (as will letting the launcher patch), which is why the order is important.
Speaking of those edits, you'll need the ones for your Intel Iris 5100. Your deviceconfig shows the card isn't currently recognized, so you'll need to edit both graphicscards.sgr and graphicsrules.sgr to add the relevant text. You can find it here:
https://bluebellflora.com/2018/07/24/sims-3-mac-players-i-need-your-help/#Filesconfirmed
Once you've done this, restart your computer, and don't open anything aside from Sims 3. You don't even need Origin—just launch the game from Applications.
If it doesn't work, try bypassing the launcher.
https://bluebellflora.com/sims-3-how-to-bypass-the-launcher-on-a-mac/
If none of this works, please check deviceconfig again, and let me know whether it shows the current [Found: 0, Matched: 1], or it now has a Found: 1 value.
