I would have to say cash rewards is the only currency with stable valuation over time. Sallie Mae (no annual fee) has 5% cash back on groceries as you mentioned several times about groceries; however 5% is only for the first $250 each month. I suppose you and your husband could each get a card if desired (Sallie Mae also earns 5x on gas and Amazon with a upper limit). If you have significant spending on groceries, you could add Everyday or Blue Cash Preferred from Amex to maximize earnings. I would suggest waiting until after you restart traveling to get the Amex Platinum card.

If you want continue to earn cash rewards, citi double cash (no fee, 2% cash back on everything) looks good. Otherwise, consider ThankYou Premier card (1st year free) as it has a nice sign-on bonus and a worthy competitor to Chase Sapphire Preferred (e.g. 1 TYP = 1.25, 50K points= $625 in airfare for those fly economy class). Nevertheless Amex SPG has always been good for non category spend (if you didn't have the card before then you'd earn the sign-on bonus), and *points would likely remain valuable for SPG hotel stays.