Looking for a flat-rate cash back card to complement my Amex Platinum and Discover IT

Hi r/creditcards, looking for some help finding a card that fills the gaps in my current setup. Here's some info below about my current situation:

• Current cards:
  • Amex Platinum, $- limit (charge card), October 2024
  • Discover IT, $14,500 limit (just got a CLI but was only $2,000…), October 2019
  • Chase Total Checking
• FICO Score: 805
• Oldest account age: 6 years 6 months
• Chase 5/24 status: 1/24
• Income: $275,000 ($150k base + $125k bonus, HCOL city)
• Average monthly spend and categories:
  • Rent: $2,900
  • Dining / going out: $1,000
  • Groceries: $500
  • Gym: $300
  • Transportation: $300
  • Shopping: $200
  • Other: $200
• Open to Business Cards: No
• What's the purpose of your next card?
  • (1) Building revolving credit history & lowering total utilization since the Platinum isn't a true credit card and doesn't help utilization;
  • (2) Earning cash back on everyday spend. The Discover IT is fine but the 5% rotating categories rarely align with my actual spending.
• Cards I've been looking at: Wells Fargo Active Cash, Citi Double Cash, Chase Freedom Unlimited – open to others.
• Category spending or general spending card? Slightly prefer a flat/general spending card – I don't want to think too hard about categories or activations. A blanket 2%+ on everything would be ideal.

Other preferences:

• No FTF would be nice but not a dealbreaker – I already use the Amex Platinum abroad when possible but it's not the most widely accepted.
• Not particularly interested in travel-focused cards as I am not the type of person to pay more for an airline ticket simply because it's a carrier I like.
• Ideally looking for a zero / <$100 AF card.
• A SUB would be a plus but not a requirement.

Any recommendations appreciated. Particularly curious if there are any less obvious options I might be missing beyond the usual suspects.