I chuckled at the part at the end, that basically says “some people voiced concerns over switching to an open source solution because of support and SLAs”. It’s like, “yoooo, you just got fucked, in a concerted effort by a large company to shed customers that ‘don’t matter’ to them. What makes you think an open source could be worse than this?”
We moved to Nutanix a few years ago and haven’t looked back. Considered Proxmox but had a larger overhead and the support wasn’t as good, but it looked pretty solid too.