I think this is a bit unfair. Most Google Takeout requests are fulfilled in seconds or minutes. Obviously collating 100GB of photos into a zip takes time.
And it’s not googles fault you have internet issues: even a fairly modest 20Mbps internet connection can do 50GB in 6h. If you have outages that’s on your ISP not Google. As others have said, have it download to a VPS or Dropbox etc then sync it from there. Or call your ISP and tell them to sort your line out, I’ve had 100℅ uptime on my VDSL copper line for over 2 years.
I was able to use Google Takeout and my relatively modest 50Mbps connection to successfully Takeout 200GB of data in a couple of days.