You're completely correct. Epic store is just a bare-bones program, it lacks features which we consider completely basic and natural in modern online marketplaces, such as a shopping cart. Yes, you have to buy and pay for games one by one.

There was this amusing incident not long ago, where the store's fraud prevention mechanisms were blocking users who bought five or six games quickly in a row. There were many, many blocked users, because at that time, the Epic store happened to have a "mega sale" event going, where many games were discounted. In a store without a shopping cart feature, that translates to lot of purchase transactions, one following quickly after another.

https://www.pcinvasion.com/epic-store-blocking-users-purchas...

If only they invested slightly more money into their store implementation, and less into buying expensive exclusive game releases, right?