Demeaning / Mean-Centering of certain values only

As you can see from the errors, data that you are working with is only available for you. The point of reprex is to provide people that want to help you with all the data that you are using. If it is only available on your computer then I can't really answer your question since I don't have the data you are trying to work with.

For example, take a look at this question:

As you can see author actually creates a fake dataset using a pre-defined function and then gives the output that they need (note the use of structure to simulate output). This way I can just copy-paste the input and output, find a solution and be sure that this solution is what you need.

It does seem excessive at first since you need to jump through so many seemingly unnecessary hoops, but in the long run it is for sure a skill that will pay off, so I can highly encourage you to try it here.

There is more help available about how to create fake datasets or even using your dataset as an input here:

Quick edit: there is also a possibly useful post explaining the idea about reprex using multiple analogies: