Guided Project: Predicting Car Prices using KNN

This is my first try at implementing a ML algorithm on a dataset. In this project I have predicted the price of cars using K-Nearest-Neighbours, creating both univariate and mulitvariate. I have tried to add some observations and understanding of the algorithm for reference.
I have also tried to get insights from the solution notebook provided by Dataquest and my fellow learners. Comparing their projects with mine, I have noticed that some of our observations are different. For example, the values of k, for which I am getting the minimum rmse is different than theirs. Also, while plotting for multivariate model, in which we relate the rmse values with k=[1,25], I am getting a plot I which the values are negatively correlated. While the ones provided by DataQuest and some other users, have been positively correlated. Kindly help me to understand as to why this mistake is occurring.
All constructive feedback regarding bad code, concept or practice and tips and advice will be much appreciated.

Thank You.

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