What differences will I notice and how much of a learning curve will I encounter?
The main difference would be their GUI(graphical user interface) but under the hood they are based off the same code(kind of).
You can upgrade to Windows 11, as you've said above but please be wary to format and reinstall your OS after you've performed the internal upgrade path since the upgrade path often times leaves behind corruption in your OS and drivers migration is half baked.
Upgrading your platform won't take anything beyond a few clicks. To reinstall the OS, you will need to create a bootable USB installer for Windows 11, then disconnect all drives except for the one you wish to install the OS onto, format and reinstall the OS in offline mode, then manually install all drivers necessary for your platform. Once you've fulfilled the prior steps, you can connect to the internet and run an update on the OS.