My farm hero saga won't upload. How can this be corrected so I don't have to uninstall and reinstall

You won't lose progress, or if you did the team could restore it. But to make it easier, always connect to either Facebook or the Kingdom so it can be tracked. You would lose any saved boosters though as they are saved in the device memory. 
The minimum game requirements for it to work happily on are 2GB. Anything less than that and that's why it struggles. Players on android, have you tried clearing cache from every last little niche? The system cache, app cache and even game cache? The trouble is sometimes only a reinstall will work .
Also something to take note of, the older devices cannot cope with the requirements either. The games have to be constantly updated to compete with newer devices and newer apps which unfortunately have a knock on effect on older ones. The reason why I decided against buying the ipad4. 
Check for updates too..

https://community.king.com/en/farm-heroes-saga/discussion/244875/having-issues-with-your-game-or-looking-for-the-latest-levels#latest

https://community.king.com/en/farm-heroes-saga/discussion/244855/game-keeps-freezing-or-crashing-what-should-i-do#latest

Don't panic @bettinats follow the instructions here and all will be restored

https://community.king.com/en/candy-crush-saga/discussion/246151/how-to-get-your-level-and-progress-back/soporto.king.com/contact