Error in install.packages : unable to translate 'C:\Users<U+5C0F><U+65CB><U+98CE>\Documents\R\win-library\4.1' to native encoding
R has problems with the non-ASCII characters in your package library path, I recommend you to set your package library in a different location.
You can change the default library folder by setting your
R_LIBS_SITE environmental variable on a .Reviron or .Rprofile file. For example:
# In a .Renviron file you can set it by adding a line like this one with the desired location R_LIBS_SITE="C:\\Program Files\\R\\R-4.1.1\\library"
For a more detailed explanation, you can read this blog post