Is it sinful to use the right hand in the bathroom, especially given the difficulty of changing and getting used to it, and the water splashing and obsessive thoughts that result from using the left hand?

The Prophet forbade the use of the right hand for istinja’ (cleaning oneself after relieving oneself), and scholars have agreed upon this prohibition. However, they differed as to whether it indicates karaha (dislike/disapprobation) or tahrim (prohibition). The majority opinion is that it is karaha, while some Zhahiri scholars held it to be tahrim. Imam An-Nawawi mentioned that the jurisprudential rule is to use the right hand for honorable matters and the left hand for less honorable matters, such as entering the lavatory. So, whoever is able to use the left hand should do so, and whoever is genuinely unable to do so bears no sin.