Let get something straight here:
- Account hacked are just email, meaning your email in/out box. Not your credit card, not your other personal area outside of email in/outbox. However if the hacker have your yahoo account, he/she might access those other areas but chances are not because those other areas such as personal information would require security key or additional question and answers like your secret question and answer. So bottom line, most likely your account hacked just your email, otherwise you would have known other area of your email got hacked.
- If you have 2FA, also known as second level of security authorization then chances are your email was not hacked, other than the hacker have your first level account password, but the hacker will not be able to login. However if you have accounts with other non yahoo services that uses same account password then the hacker can use it to tried and access your account. However again, if you have 2FA activated on other non yahoo service then you are also safe. I would say 99.99% safe everywhere if you have 2FA turned on.
- Bottom line. Turn on your 2FA everywhere, if 2FA is not available on services that you’re using then use another brand or services that offer 2FA.