Hi there 
The previous case (Can't Import Maps) had since been resolved as mentioned here.
I don’t think what is currently occurring is the same issue, the image there shows a 408 Request Timeout - HTTP | MDN which usually means that there is a timeout waiting to receive data from the browser.
We’ve run into this issue a couple of times in specific regions when there’s some form of issue with routing. It’s generally not an issue that would show as poor upload or download speeds, because the issue is somewhere in the route between the user and the assets server rather than between the user and the speedtest server.
One important thing to test is to try the upload with a different connection (such as mobile tethering), or with a VPN or VPN-like service such as Cloudflare WARP which would use different routes.
If a different connection resolves it, then it’s likely a routing issue. If it doesn’t, then there may be something else at play.