Need help choosing a credit card for travel

Hello there! My wife and I are financially in a position where we can travel more (yay!), and need help deciding on a good credit card in terms of airline miles and rewards. My old credit card is currently a Discover student card from back when I was in college, and it doesn't have the best rewards for travel. I don't have a super old credit history (5-ish years), but my score is very good (I've never missed a credit card or mortgage payment, and we don't have really any debt), and I don't believe it will be an issue.

I would prefer to have a card without any annual fees, but I'm willing to consider them if the rewards are good enough. This card is something that would be used to book airfare, lodging, and activities for travel, but also for daily purchases like groceries and gas. We really enjoy going on cruises, and are planning to take one every other year in the future. We plan to travel internationally once per year. We prefer to fly with Delta (home airport is PDX), but we will book with other airlines if the prices are significantly lower. We fly on average 1-2 times a year currently, and I see that number staying fairly consistent as neither of us needs to travel for work.

I've looked into some of the cards through Delta and Chase, but I get pretty overwhelmed with the options. I'm hoping to get a few good recommendations here.

Thanks!