It's not an ideal solution but you can save your Google takeouts to Dropbox. It might be worth signing up for Dropbox for one month and use Dropbox's sync features. I haven't used Dropbox in years but they used to have quite solid syncing.

Not really helping you here. But when I started using Google Photos, I still manually downloaded files from my phone to local storage. I did this mainly to ensure I have the original copies of my photos and not some compressed image. Turns out that was a wise move as exporting photos from Google is a pretty damned awful experience.

Im surprised that feature exist tbh. It worked fine for my 20GB splited into 2GB archives if I remember correctly

A 50GB download takes less than 12h on a 10Mbps internet. And I had a 10Mbps link 10 years ago in a third world country, so maybe check your options with your ISP. 50GB really should not be a problem nowadays.

You need a solid wired connection. Maybe phone a friend for help.

Alternatively you could use curl. I think it as a resume option.

It sucked when I closed my accounts years ago. I had to do it manually for the most part.

I do occasional smaller "takeouts" and haven't had any issues.

I have an "automatic album" (or whatever they call it) where all the photos of friends and family (even pets) get automatically added to it. Then I can just request a "takeout" for that one album, since those are the photos I actually care about. It's a much smaller download than the entirety of my Photos account.

Find a way to borrow more bandwidth.