There are many people who have transferred significantly more-you should be fine.
As far as the amount of data you’re using on each, I wouldn’t be concerned. There are people with hundreds of TBs on each platform without issue, you start to run into problems if you’re accessing data too much or too frequently/hitting their servers a lot. If you get ‘locked’ from either Amazon or Google it will likely only be a temporary (<24h) way of throttling you.
50TB copy from Amazon DE to Amazon UK to GoogleDrive (encrypted ) to GoogleDrive (unencrypted)
p.s. Amazon will lock you once you pass 2Gbps constant upload/download ( its an estimate that I base on my experience using 3 different 1Gbps server to handle the data )