Stop using Excel files and instead create PDFs since you only need to view the information.
When I got my Galaxy S7, I could open an Excel sheet to view. Viewing is all I need to do; I send the updated files from my desktop from time to time. I don't recall what app was originally used to open it, but after an update awhile back, it didn't work anymore. I had to install MS Excel for viewing. The problem with this is needing internet connection for it to work! Many times I have neither wireless or cell connection. So, is there an app I can use to view my own Excel files without connection? Thanks.