Is the Hadith true regarding Abdullah ibn Unays killing Khalid al-Hudhali and bringing his head to the Prophet, may Allah's peace and blessings be upon him?

This hadith (definition) was narrated by Imam Ahmad and Abu Dawud from Abdullah ibn Unays, who said: "The Messenger of Allah (peace be upon him) sent me to Khalid ibn Sufyan al-Hudhali to kill him. I saw him, and the time for Asr prayer had arrived. I feared delaying the prayer, so I walked while praying, gesturing towards him. When I drew near to him, he asked me, 'Who are you?' I said, 'A man from the Arabs. I heard that you are gathering forces for this man, so I came to you for that.' He said, 'Indeed, I am engaged in that.' So I walked with him for an hour until, when I had the opportunity, I struck him with my sword until he died."

Abu Dawud remained silent about it, and Ibn Khuzaymah and Ibn Hibban authenticated it. Al-Nawawi, al-Iraqi, and Al-Hafiz Ibn Hajar considered its chain of narration to be good.

As for the narrations that mention cutting off his head and carrying it to the Prophet (peace be upon him), such as the narrations of Ibn Shabbal and Al-Waqidi, they are very weak and not established because they are either mu'dal (problematic, missing a link), munqati' (broken chain), or narrated by liars.

The authentic narrations are limited to his killing without mentioning the cutting off of his head and carrying it. Many scholars have agreed that no head was ever brought to the Prophet (peace be upon him). It has been reported that Abu Bakr al-Siddiq denounced the carrying of heads to him, saying: "Are you imitating the Persians and Romans? Let no head be brought to me, for a letter and news suffice me."

And Allah knows best.