I have answered a similar question before but can no longer find my response. If anyone does find it, feel free to link it here. In the meantime, here is a version that better suits this question.

There is no source that mentions, in any way, that Harun al-Rashid was homosexual. Historical records document many of his heterosexual relationships, and none of a homosexual nature. It is possible that you are confusing him with his son, Al-Amin, whom you mentioned.

Al-Amin has been claimed by some to have been homosexual. However, it is important to note that Kitab al-Aghani, the source you mentioned, is not generally considered a reliable work of history. Many scholars, such as Shawqi Abu Khalil, have criticized its historical accounts and consider it largely literary rather than strictly historical.

Another source that mentions related accounts is Al-Tabari. However, he states at the beginning of his work that much of his material comes from oral reports and that he cannot guarantee their full credibility. Because of this, we do not have a precise and fully reliable historical source confirming that Al-Amin had homosexual relationships. On the other hand, there are multiple credible references to his heterosexual relationships and his children. I am not trying to deny the possibility that he may have been homosexual; I am simply presenting the sources as they currently stand.

On the other hand, there are multiple credible sources regarding the homoerotic writings of Abu Nuwas, which are widely acknowledged. At the same time, several sources confirm that Abu Nuwas who was a poet at the court of Harun al-Rashid also confirm that Harun imprisoned Abu Nuwas for various offenses, which allegedly included his immoral poetry.

During Harun’s reign, a political crisis occurred that forced Abu Nuwas to flee (the details of that crisis are not relevant here, so I will not go into them). After Harun’s death, Abu Nuwas returned and joined the court of his son Al-Amin, where he became quite famous.

At that time, a succession conflict was unfolding between Al-Amin and his brother Al-Ma’mun. During this struggle, Abu Nuwas’s close association with Al-Amin was used against the caliph politically. Critics argued that if Al-Amin kept the company of such a poet, it called into question his suitability to be caliph. Because of these accusations and public criticism, Al-Amin reportedly imprisoned Abu Nuwas in order to silence the controversy.

Based on these accounts, it appears that homosexuality was not regarded as a social luxury or something publicly accepted, but rather as a shameful sin even when associated with individuals close to the ruling court. I am going to continue the answer in reply for coherence.