I have these two alarms on my Vsphere and yet I have almost all the resources free.
-Insufficient capacity on DID cluster to meet resource configuration in Datacenter .
-Insufficient resources to meet vSphere HA failover level in DID cluster in Datacenter.
Ideally you will need 3 or More EXSI hosts for HA failover to be working and configured properly. Also are you using a shared Datastore between these hosts?
First of all, which Admission Control policy have you configured? Then, how many resources did you set aside for restarts? And next, do you have reservations on VMs?