Which credit card is good to purchase air ticket online?

Hello, I am not a frequent traveller, before covid, will only travel at most 4 times per year (at least twice a year). I am going to book my travel stuff and my air ticket will cost around S$1500. I did some research and found these credit cards:

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1. DBS Altitude credit card ($1 = 5 miles equivalent to around 3.62% rebates if I redeem the fairprice voucher). Am I right to say that DBS Altitude seems better than Citi Premiermiles in terms of buying air ticket?
2. OCBC 365 credit card which gives 3% cash rebate for spending $800 and more.

Did I do my research correctly? Which of the 2 credit card is better?

Are there any other credit card which offers even better miles or cash rebates?

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Thank you.

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