Does violating the prophetic method of istinja (cleansing after defecation or urination) by using only water and the left hand affect one's entry into the highest Paradise (Jannat al-Firdaws al-A'la), or are good deeds sufficient for entry?

"Istinja (definition)' (cleaning oneself after relieving oneself) with water only is part of the Prophet's Sunnah (definition), not contrary to it. This is based on the narration of Aisha (may Allah be pleased with her) in which she mentioned that the Messenger of Allah (peace be upon him) used to perform istinja' with water, and his saying about the people of Quba: 'They used to perform istinja' with water, so this verse was revealed concerning them.' It is also supported by the hadith (definition) of Anas ibn Malik regarding his performance of istinja' with water. Performing istinja' with water only does not prevent one from attaining the highest level of Paradise if they strive in obedience to Allah."