How many medium size migrations have you done? Its never that easy even if you are just hosting a bunch of VMs. Let alone if you are using any cloud specific services.
I have been involved in a few on the periphery working in cloud consulting (first at AWS itself and now an outside company). I actively avoid the “lift and shifts”. I come in for the “modernize” portion.
https://www.synatic.com/blog/lift-and-shift-vs-modernization
Done? none, I wouldn't do it. Undone after it failed, one, and helped some other people in others.
You are expecting people to act rationally in a way that will succeed. That's not how a lot of places out there operate.