The Messenger of Allah ﷺ would give the salam after every two units and pray a single unit as witr.
حدثنا أبو بكر بن أبي شيبة حدثنا شبابة عن ابن أبي ذئب عن الزهري عن عروة
كان رسول الله ﷺ يسلم في كل ثنتين ويوتر بواحدة
Reported by Muslim, Prayer of the Traveler, chapter on the night prayer and the number of units the Prophet ﷺ prayed at night, etc., hadith 736b, from the hadith of Zuhri, at length, and Busiri said, this isnad is sahih, its narrators