The Companions of Muhammad (ﷺ) didn't consider leaving anything to be disblief except for the Salat.
Jami` at-Tirmidhi Book 40, Hadith 17
← Previous Hadith that the Messenger of Allah (ﷺ) said: "The covenant between us and them is the Salat, so whoever abandons it he has committed disbelief."

Jami` at-Tirmidhi Book 40, Hadith 16 Next Hadith → that he heard the Messenger of Allah (ﷺ) say: "Whoever is pleased with Allah as (his) Lord, and Islam as (his) religion, and Muhammad as (his) Prophet, then he has tasted the sweetness of faith."

Jami` at-Tirmidhi Book 40, Hadith 18