What to get for a joint spending card? (current Sapphire user)

Hi,
I've had a Chase Sapphire Preferred for 10+ years that I use for everything, and I like it mainly for the travel redemptions. It's the only card I've ever had and I spend on average 4–7k/month on it. I live in NYC, don't buy gas, spend a lot on food.

My wife and I are now setting up a joint setup for shared expenses (mostly groceries, houshold, travel, etc.) and that will probably be another ~6k/month on a second card. (& will probably decrease Sapphire spend down to 2-3k/month)

I mostly just like getting us free flights each year and haven’t really gone deep on optimizing beyond that.

Trying to figure out the best way to structure this without overcomplicating things. I was originally thinking Freedom Unlimited for the joint card so we can pool points into Sapphire and get more free flights, but I’ve seen mixed opinions on it and not sure if there’s a better setup I’m missing.

Goals are:
keep things simple
maximize rewards (mostly travel)
avoid having to track a bunch of categories/cards

Should I go with Freedom Unlimited as a catch-all? or go outside Chase entirely for the joint card? Is there something I'm not considering here?

Thanks in advance!