Learn Hardcore Hebrew: החיסרון הגדול הוא שהמשרד רחוק, אבל יש גם יתרון אחר. - The big disadvantage is that the office is far away, but there is also another advantage.

Breakdown of החיסרון הגדול הוא שהמשרד רחוק, אבל יש גם יתרון אחר.

Why does החיסרון הגדול have ה־ on both the noun and the adjective?

Because in Hebrew, when a noun phrase is definite, the adjective usually becomes definite too.

So:

This is a very common Hebrew pattern: if the noun is definite, matching adjectives normally take ה־ as well.

Examples:

Why is there a separate הוא in החיסרון הגדול הוא ש...?

This הוא works like is in a present-tense sentence.

Hebrew usually does not use a present-tense form of to be in simple sentences:

But when the sentence links one thing to another, especially when the second part is a clause, Hebrew often uses הוא:

So here הוא is not really the pronoun he. It is functioning as a kind of present-tense copula.