With NSX-T If I want to resize the appliances, I can deploy a new manager on a new IP and then delete one of the old ones. Repeat for each manager so that I end up having three identically sized managers. However, with an NSX-T Deployment on VCF, the delete appliance option stays greyed out. Is there any reason why this is happening? I have gone through different documentation and have not come across a reason why. Most articles on redeploying these managers are specific to NSX-T and not VCF.
Even with VCF deployment, you should be able to delete nsx-t appliances from NSX-T manager UI. can you share version of VCF you are running and possible screenshot from NSX-T UI ?
You should really open a support case to assist. Based on the need it can be escalated to engineering , if required.
You can resize it with using API .