First post in this board, but have been lurking around for awhile. I feel like I "know" you all and would appreciate your advice

I'd like to apply for a new card but really am not sure there is a need, which one would be best, if I have something already that could be changed OR be using what we have in a better way. The only rewards I have ever used are our Disney dollars. I have Chase rewards on the Freedom but have never used them or cashed them in.
Thank you in advance for any thoughts or advice you may have!!
We have the following cards and haven't applied for a new card since 2014. Currently we only spend on the Chase cards. The Amex is the "emergency" card and doesn't get used. If I'm interested in the Amex Gold perhaps I should reconsider using this one more often?
- Chase Freedom
- Chase Disney Premier
- USAA Cashback Rewards Amex
- We spend approx $2000-$2500 on our cards each month and have recently started using them for all expenses (grocery, fuel, electric, tv, phone, etc)
- We payoff our cards each month and do not carry a balance.
- We aren't traveling at the moment or foreseeable future
- We fly Delta and Southwest primarily
- Marriott preference since we do have Marriott rewards account
- I recently started my own small business as a consultant this year so I have separate business checking/savings but no CC related to the business. I would like to have a credit card available so I'm not using the debit card linked to the account. Currently the business has very few expenses since I do much of my work remotely.