Car dealers are commonly known as secondary dealers. Usually car dealers can give you a lower price.
The difference between car dealerships and 4S is that 4S is a service unit directly affiliated with the car brand. Both after-sales and maintenance and repairs are relatively standardized, and consumers are relatively more assured.
Car dealers are actually similar to "group buying and wholesale". They ask 4S to buy cars in large numbers, and their prices are naturally much lower than the prices for individual consumers to buy cars directly from 4S. Therefore, the car dealer can still guarantee profits after transfer.
In terms of purchase price, of course it is cheaper to purchase a car from a car dealer. But the formality of after-sales service is naturally not comparable to that of 4S. Therefore, my personal opinion is: Cars that are widely owned and very easy to maintain can be bought from car dealers because they are relatively cheaper. Generally, consumers of other vehicles can consider it based on their understanding of vehicle maintenance technology.