Network speeds can vary drastically that is expected. However seeing that your upload is no way comparable to your download is strange.
I would just like to know what tools you are using for speed testing and if you get the same results from different tests.
Without testing the device I could only suspect that this may be a firewall/data restriction on the device. Can you ensure that your device is not putting data caps on upload and potentially try a different speed testing service.
Low upload speeds would be more apparent when video calling. If you can test that and are able to communicate via video call that would suggest to me that your upload is in fact a lot higher than you suspect.
If you haven't done so already please reach out to the web chat team for some trouble shooting.