In general you should have between 1 to 3 active credit cards although you can also have 5 active credit cards to help bring stability to your credit.
It's generally recommended that you have no more than 3 active credit cards unless you're really financially stable and can easily pay them off.
The 2 factors that contribute to your credit score are the number of credit accounts and the type of credit accounts you have.
If your goal is to get a good credit score or maintain a good credit score, then 2 or 3 credit card accounts is a good idea, in addition to other types of credit, are also recommended.
This combination of credit accounts can help improve your credit mix and credit history and credit score.
Generally it's a good idea to only have 3 active credit cards and use them responsibly and pay them off on time to help build your credit.
If you have more credit cards and use them without being able pay them off then that can lower your credit score.
Having accounts open with a credit card company will not hurt your credit score, but having zero balances will not prove to lenders that you are creditworthy and will repay a loan.
Lenders want to make sure you repay, and that you will also pay interest.
There is no ideal number of credit cards you can own.
You can own as many credit cards as you want as long as you are eligible for it.
However, having multiple line of credit can make you look like a desperate borrower and increases the overall available credit.