"Dekiru" expression is often preferred in formal situations, while "-rareru" is more casual and conversational. The advantage of using "dekiru" for beginners is that you don't need to think about the conjugation. With "-rareru" form, you have to change the verb forms. ,You just need to add "kotoga dekiru" after a verb in dictionary form if you use "dekiru". You will have to learn the conjugation eventually, but "dekiru" works perfectly for the meantime. Also, "dekiru" itself is "-rareru" form of "suru." For example, わたしは　テニスを　する。I play tennis. →わたしは　テニスが　できる。I am able to play tennis. インターネットでホテルの予約をする。I book a hotel online. →インターネットでホテルの予約ができる。I can book a hotel online. There is no "dekirareru." You're right.

taberu koto ga dekiru taberareru These mean the same thing.