While I sympathize being in a similar position myself, adding a new cluster to an existing vCenter with distributed switch and doing storage vmotion is quite friendly. In Hyper-v/Azure Local land you can use the Azure migration tool however and your downtime is largely limited to the length of a reboot. Not zero downtime like vmotion can provide but not that bad. I did it for 300 VMs to get to Nutanix AHV using Nutanix Move which is very similar.
Changing platforms alltogether is always going to come with some heartburn. if you were only using basic features then its pretty easy. If you were using NSX and need to migrate to Datacenter firewall then heaven help you, they are not the same. SCVMM does a lot of the heavy lifting there but man, in a HA environment it sure requires a lot of resources compared to vCenter.
For me, the amazing part of all of this is that it used to be good enough to know one platform, these days you have to be proficient in several to be successful.