Secure access to Dropbox through R as a part of a shinyapps.io website

I am looking for someone to create a secure access to Dropbox through an Rscript that will be integrated with an shinyapps.io website. I need an intermediate level of security to be implemented and have a preference for the RDrop2 or httr2 R packages to be used for connecting to Dropbox. The Dropbox files will need to be accessed and updated daily through the shinyapps.io website. The main concern is that the public nature of the website must not compromise the security of the Dropbox account, so app secrets and other sensitive information must be hidden, encrypted, or otherwise kept safe. The nature of the access must also support an indefinite lifetime for the website (access tokens don't go stale and website fails to load neccessary data from Dropbox)