Connect Write to ftp Site

I have a process where I need an automated process to write a series of files on a daily basis to an ftp site. There are series of files that are written as both csv and xlsx that need to be written to the ftp site. We have RStudio Connect installed and could use a schedule RMarkdown but I'm not sure about options to handle the Excel files.

For example, I could use pins to create csv files hosted on Connect and then RCurl to post them on the ftp site. As far as I can find pins does not support xlsx files and I'm not sure what happens on RSConnect if I write an excel file from the Markdown used xlsx. Where would the file get saved?

Ideally there would be a way to write these files directly to the ftp directory, but I cannot find examples of that. It seems I need to write and then transfer.

Any ideas or help would be appreciated.