Removing Max Upload File Size

We often have issues with Dropbox not syncing and have to upload photos manually. If they sync from dropbox, there is no cap on how big the file size can be, but when we do it manually there is a cap of 20mb. Our files are usually bigger and we have to resize everything when they don’t upload. It’s a massive pain. I don’t know why one way has a cap on the file size while the other doesn’t, but if that could be removed or increased that would be amazing, thanks.