Windows 11 Home only. Pro, Enterprise, and Education don't have this requirement.

Are any of these freely sold to individuals, or do you only get them as part of larger deals?

Pro is sold to individuals and you can easily get a laptop with a Pro license from an OEM.

Seems like there's also Pro for Workstations. Also, full disk encryption seems to only be available in Pro?

Yes. Well, BitLocker is in Pro, Pro for Workstations and Enterprise. Same for Hyper-V, if that matters to you; not available in Home.

Home edition is for non-commercial use. I don't know if that's in the EULA or not, but that's the use case that Home is meant for.

Pro and higher are for work use cases, and features add on as you go up the line. Pro for Workstations and Enterprise support slightly different feature sets, IIRC. Creating new ReFS filesystems is only available on Pro for Workstations, for example.

The other benefits of Pro for Workstations is a higher RAM limit (2TB vs 6TB) and socket count (2 CPU sockets vs 4 CPU sockets), NVDIMM-N support, and SMB Direct. Not normally features that would be missed on a normal PC.