The Messenger of Allah ﷺ used to perform much of his prayer while seated.
حدثنا أبو نعيم قال حدثنا عبد الواحد بن أيمن قال حدثني أبي
كان رسول الله ﷺ يصلي كثيرا من صلاته وهو جالس
Its isnad is sahih. Abdul-Wahid bin Ayman Al-Makki Al-Makhzumi, their freed client, is trustworthy, and his hadith appears in the Sahihayn. His father, unnamed, is likewise trustworthy, and his hadith appears in Bukhari.The hadith was narrated by Muslim, 1/506, no. 732, in the book of travelers, Abu Dawud, 1/251, no. 956, in the book of prayer, Nasai, 3/222, no. 1656, in the book of night prayer, Tirmidhi in Shamail, 235, no. 266, and Ibn Khuzayma, 1/270, no. 539.