'A'isha reported: When the Messenger of Allah ﷺ grew bulky and heavy he would observe (most of his Nafl) prayers sitting.
The Prophet Muhammad's example shows us that it is permissible to pray while sitting if one cannot stand due to physical limitations or any other reason. It also teaches us the importance of perseverance and dedication towards fulfilling our religious obligations despite any difficulties we may face in doing so. Furthermore, it reminds us that Allah SWT knows best about what is good for His servants and He will guide them accordingly if they seek His help with sincerity and faithfulness.