Mac Pro 2010 with High Sierra and metal video card

So I have a Mac Pro 2010 with High Sierra and a metal compliant video card, but Sims 4 says it can't recognize the card.  I've tried finding a way to get it to work, stumbled upon a thread on how to add the card to the graphics list, but that's IF you can get Sims 4 installed to applications instead of through Origin.  I can't seem to find a way to get it to work outside Origin or get it to install as it's own app.  My wife owns the game and I'm trying to get it working for her.  Still getting prompted to install legacy edition.  I saw @Bluebellflora has gone through this but I keep hitting a wall. I would certainly appreciate the help, thanks!

Specs:

Mac Pro 5,1 2010

32 gb ram

Geforce gtx 470

High Sierra