Two thumbs up dev(s), hope you're doing okay and getting some sleep in between. Had some rough production upgrades in my life, and this sounds like a pretty bad one. ๐
They probably need to do their database migration on a computer with more memory.
I had a migration that was still running after 16 hours. Finally just for fun I tried it on another server with 64 GB of RAM and it was done in 15 seconds.