To create a reprex you also have to render (create) a document.
So it looks as if this are not two problems but only one.
Looking at your message ' ........ /Rterm' not found' I conclude (?) that the folder with the R exe-files is not in your (Windows) path.
Is it possible for you to add that to your path?
You succeeded in starting R, so you must know where it is located.
When you use a shortcut to start it, then look at the 'properties' of the shortcut to find out where the exe-file is located e.g. with 'Open File Location'.
I hope this gives you some ideas how to solve it.