Should I get a 3rd credit card? 21 y.o. incoming med student – wanting to use my JetBlue card less

TLDR: I have 2 credit cards, but one of them is a JetBlue card and I want to use it less due to their uncertain future. Should I move primarily to using my M&T Signature Visa, or should I get a new card (if so, which one)?

• Current cards:
  • M&T Bank Visa Signature – $12,000 limit (3yrs)
  • JetBlue Card – $9,000 limit (1yr)
• FICO Score: 811
• Oldest account age: 4 years
• Income: 
  • ~$2,000 monthly, but will soon be $0 since I'm starting med school this summer
• Average monthly spend and categories (projected):
  • dining: $80
  • groceries: $300
  • gas: $100
  • travel: $100 (mostly in summer)
  • other: $150
  • rent can't be put on CC so I didn't include
• Open to Business Cards: 
  • No
• What's the purpose of your next card? 
  • Not too sure if I even need one tbh, I'm looking to use my JetBlue card less as the airline's future is mildly concerning. Would love to maximize rewards but I don't want an annual fee.
• Do you have any cards you've been looking at? 
  • Chase Freedom Unlimited
• Are you OK with category spending or do you want a general spending card?
  • General spending

Thanks!