While not completely up to my own standards, this is pretty neat and readable: https://rclone.org/install.sh
I may add more if I have time today.
Must say I'm pleasantly surprised.
Yep, my experience of this was at google, where I heard "gbash is actually pretty good!", so I learned that system well (because shell scripts are incredibly useful!), but still found the results unsatisfyingly inscrutable.
I challenge you to find a single easily readable >100 line bash script and link it here (I do think small scripts can be fine).