Need my credit to increase, what credit card do you recommend for this?

Since June 2025 I’ve been paying off my credit cards and finally cleared all my balances last month. I closed one credit-union card in July, paid off another credit-union card last month, and also helped pay off an Amex shared card (though I’m not the primary holder so it didn’t impact my credit). I’d like to add another credit card now to help boost my credit score, but I’m unsure which one to apply for. I’ve heard mixed things about Credit One and Capital One.

Has anyone had success with certain cards, and did you close them once your score improved? I don’t want to apply for a card and later on hate that decision because of the position I was in.