The number of credits does not affect the amount of benefits you receive. It only determines if you are eligible or not. You do not get extra benefits for earning more than the minimum number of credits.
How much do I need to earn to get a credit?
The amount of earnings it takes to earn a credit may change each year. In 2020, you earn one Social Security or Medicare credit for every $ 1,410 in covered earnings each year. You must earn $ 5,640 to get the maximum four credits for the year.
And how many credits do I need for retirement benefits?