The Messenger of Allah ﷺ did not pass away until most of his prayer was performed sitting, except for the obligatory prayers. The deeds most beloved to him were those done consistently, even if small.
أخبرنا إسمعيل بن مسعود حدثنا خالد عن شعبة عن أبي إسحق قال سمعت أبا سلمة
ما مات رسول الله ﷺ حتى كان أكثر صلاته قاعدا إلا الفريضة وكان أحب العمل إليه أدومه وإن قل
[Its chain is sahih] Ibn Majah narrated it in Iqamat al-Salawat, chapter, "On Performing the Voluntary Prayer While Sitting," no. 1225, 4237, from the hadith of Abu Ishaq, with the same wording, and it is also found in al-Kubra, no. 1359.