Points & Miles Card for Saving Up For a Trip?

I've been watching a lot of aviation YouTube videos lately, of people trying out different flights, often in Business or First, and they say they don't pay much for it at all because they earned points/miles with a travel credit card.

But it seems like those rewards cards only give higher rewards when spending on travel, which is not helpful if you're not spending on travel, but eventually saving up for travel.

These YouTubers allowed me to imagine flying in first class one day, and even if I do it only once in my life, I kind of want to start saving for it relatively soon, but won't be spending a lot on travel at the moment (for obvious reasons, but even putting the pandemic aside, I don't travel too often). And since it'd potentially be a once-in-a-lifetime experience, I'd want to save for a long time and redeem it on a long flight from the US to, say, Asia or Australia, to make the most of that flight experience.

Is there a card that gives good miles rewards for the kinds of spending people do at home?

I'm not looking for a card right now, and I know it depends on the airline, how far I'd be going, and what my current spending looks like, but want to know what my options might be when I do want to apply.

Just generally, my credit score is \~730 (vantage score), I just graduated college, so low spending (\~$250/mo total) and no 'real' income, but will only be applying for a new credit card in over a year when I actually have a stable income and do more significant spending. Currently, I have a Discover it card that I opened in 1/2019 and just opened the PayPal cash back card this month (another reason not to open new cards for a while). My general philosophy is no-annual-fee cash back cards, and if did not want to save for a trip, I'd want to apply for a cash back card that is better for either groceries or restaurants, but the whole cash back idea doesn't seem to be helpful for saving points for a higher-fare trip.

What are your thoughts?