I'll suggest USPS.com

USPS is an independent agency of the U.S. federal government. They have around 13M visits per day [1]. Their website looks modern although I'm uncertain about their uptime.

[1] https://analytics.usa.gov/postal-service

and 90% of those visits are probably a GET request with a tracking number

Depends what you consider to be large files, and admittedly its not a free for all upload, but gov.uk probably fulfils most of those requirements.

well a simple video on social media can be 100s of MB or even more than a GB, without even thinking about livestream