How much data and traffic can 1 database successfully handle?

[YaBoiSmokey]

Good evening... I am at the beginning of the project and trying to idealize the system. I couldn't make a decision on this very critical issue; * There are 50,000 rows for 50,000 products * The 50,000 rows (most of which are char: less than 255 characters) have 250 columns. 1st SCENARIO; * This site is used by 100,000 people daily just to view the products 2nd SCENARIO; * This site is used by 500,000 people daily just to view the products 3rd SCENARIO; * This site is used by 1,000,000 people daily just to view the products 4th SCENARIO; * This site is used by 5,000,000 people daily just to view the products 5th SCENARIO; * This site is used by 5,000,000 people daily to both view and shop for products. 6th SCENARIO; * This site is used by 10,000,000 people daily to both view and shop for products. Keeping all this data in one database is definitely practical... HOWEVER: Keeping all the data in one database, WHICH SCENARIO(S) IS SUITABLE FOR? LOGICAL? DOES NOT CAUSE CRASHES OR SPEED ISSUES? WHICH SCENARIO(S) IS PROBLEMATIC? ILLOGICAL? CAUSES CRASHES OR SPEED ISSUES? IF YOU WERE TO DIVIDE THE DATABASE INTO 2/3/5/10, WOULD YOU DO IT? IS THIS NECESSARY? One of the large-scale websites serving nationally (such as sahibinden, getir, yemeksepeti, hepsiburada, n11, etc.) HOW MANY DATABASES WOULD YOU USE IF IT WERE YOURS?