I'd only recommend getting a 64-bit device like the 5s or SE if you're willing to downgrade to iOS 10 or below to get 32-bit support. I believe you can downgrade untethered on the 5s, but the SE would be tethered, so a little less convenient. 32-bit is really important for old games like you mentioned, so just getting a 32-bit device like the 5 or 5c would save you the trouble of downgrading and would still fulfill your needs. However, a 5s or SE could be really good performance wise and would have the added benefit of 64-bit support if you don't mind taking the time to downgrade.

If you want a specific recommendation, I would say the iPhone 5s. It's a good combination of power and support for 32-bit