Credit Card Recommendations welcome!

Hey everyone, I've recently become aware of the amount of different cards and directions that you can go with rewards and was looking for some insight.

Essentially, I'm using the Freedom Unlimited for everything now but was looking to expand, but wanted to get some more experienced opinions.

CREDIT PROFILE

* Current credit cards you are the primary account holder of:

* Capital One Platinum, open in 8/2020, 8k limit.

* Chase Freedom Unlimited, open in 2022, 30k limit

* FICO scores with source: FICO 740

* Oldest credit card account age: 6 years

* Cards approved in the past 6 months: 0

* Cards approved in the past 12 months: 0

* Cards approved in the past 24 months: 0

* Annual income $: 85000

CATEGORIES

* Ok with category-specific cards?: Yes

* Ok with rotating category cards?: No

* Estimate average monthly spend in the categories below.

* Dining $: 400

* Groceries $: 500 Costco

100 other local grocers

* Gas $: 250, usually all costco

* Travel $: 300

* Using abroad?: yes, no short term plans for this card

* Other categories or stores:

* Other spend: Gym membership, Spotify, Amazon Prime. Other than that there aren't many recurring expenses.

* Pay rent by card? No

MEMBERSHIPS & SUBSCRIPTIONS

* Amazon Prime member: Yes

* Costco or Sam's Club member: Costco

PURPOSE

* Purpose of next card: Travel Rewards

* Travel rewards preferences: United/Marriot

* Cards being considered: The rewards that come with Amex seem appealing and I think that I could make use of them, but I want to see if there is something that may be better. I think the rewards on the Freedom Unlimited are solid, but was looking to upgrade and see if there is something that may be better for travel or cash back.

Thank you so much for your time.