Does a person's imagining himself reciting the Qur’an to a group of people so that they may be affected by it as he was, while he chants it in private acts of worship, fall under showing off (riya’) or self-admiration (ʿujb)?

The servant's joy when people come to know of his good deed that he had concealed is considered a subtle form of showing off (riyaa'), but it does not invalidate the deed as long as he did not make it public or speak about it. However, if he spoke about it with the intention of gaining people's praise, this falls under seeking reputation (sum'ah), which is blameworthy like riyaa'. It is narrated in the hadith: "Whoever makes his deeds known (to gain reputation), Allah will make him known; and whoever shows off, Allah will expose him."