Hi. I have the EXACT same issue and it starts to piss me off because, same as you, I also paid for a 1T
capacity plan and I have more than 700G to upload to the cloud.
I have already spent 3 days trying to progress on the task of uploading all my photos and videos to the cloud and every single time Lightroom tells me 'not connected to the server' after some files uploaded then if I cancel sync and launch it again, Lightroom get reconnected to the cloud server - but definitively I don't want to do it manually every 10-15mins.
So it is totally unacceptable in terms of product experience and I ask Adobe tech support team to provide a workaround/fix for this issue as soon as possible.
Looking forward to a prompt response from the Adobe support team.