Upload speeds, on many internet connections, have been known to be capped -- typically a provider-enforced cap. What type of connection are you using remotely? Fiber, cable, hotspot, etc.?
Because of this cap, uploads are going to be even worse when not on your network directly, in some cases -- say, attempting to upload something from a coffee shop.
That may explain the poor speeds, although there could be other factors. Sorry to respond with bad news!