VMSS instances manual upgrade to the latest image in compute gallery

**Related command**
I am trying to manually change image in VMSS which is stored in my own compute gallery. Current behavior does not make sense to me. I always somehow update the model and reimage the VMs but it is very unintuitive.

**Is your feature request related to a problem? Please describe.**
My setup:
- uniform VMSS behind loadbalancer created from my custom generalized image with the `latest` flag
- generalized images stored in compute gallery (Ubuntu 22)

What am I trying to achieve:
Every time I build and capture a new generalized image with the flag `latest`, I want all the VMSS instances latest model to be set as NO.

**First problem**:
What is the point of `latest` flag when I must update it manually every time I publis new image? With this command I can tell VMSS there is new "latest" image and instances change latest model to NO:
`az vmss update --resource-group myResourceGroup --name myVmss --set virtualMachineProfile.storageProfile.imageReference.id=/subscriptions/xxx/resourceGroups/xxx/providers/Microsoft.Compute/galleries/xxx/images/myImage`

Here comes the **second problem**, If I don't update instance to latest model, but straight reimage the instance, new image is replaced but, the latest model still showing as NO. I expect to reimage the instance with the "old" image and not the `latest` because the instance model has not been updated yet.

**Describe the solution you'd like**
I would like to mark VMSS instances latest model as NO always when the new `latest` image is pushed to the compute gallery.