If you had asked me about NVIDIA, since I run Wayland on Linux, I would have probably been much more biased.

Regarding the last point, you can learn more about it here:

https://wiki.archlinux.org/index.php/Intel_GVT-g

Or, on their official GitHub Wiki:

https://github.com/intel/gvt-linux/wiki/GVTg_Setup_Guide

AMD's similar MxGPU is only available on Radeon Pro and their Workstation graphics:

https://www.amd.com/en/graphics/workstation-virtual-graphics

Regarding other factors to consider, I really don't have anything else. If ECC is important, then as you mentioned Intel doesn't offer ECC on these chipsets.

Additionally, AMD's advanced security features like memory guard is only available on the PRO processors, however there are versions of the 4650GE Pro and 4750GE Pro for a descent price point:

https://www.amd.com/en/technologies/pro-security

More advanced capabilities like SEV are only supported by EPYC from what I can tell, which is what various cloud providers are now using for confidential computing:

https://www.amd.com/en/processors/amd-secure-encrypted-virtu...

Intel offers SGX on most of their consumer chips, but it has been plagued with issues and exploits in the past:

https://en.wikipedia.org/wiki/Software_Guard_Extensions