The first thing that you consider if you will be replacing an HCI node is that you should always have backups of your whole cluster.

The reason for this is that whatever happens to your cluster and VMs during the node replacement, you will always have a backup which you can restore from.

The other things that you should also consider are the following:
Network configuration - you should prepare the network config for you new node.
Hardware compatibility - your new node should be compatible with your existing cluster. Better to consult the technical guides.
Time synchronization - your new node should be able to synchronize with your existing cluster to avoid any issues
Disaster recovery plan - If you cannot afford to have a production downtime, it is much better to have a disaster recovery or fail over plan for your VMs while you are performing the node replacement.

I hope this can help.

Data Backup, Check Node Health, Cluster Status, Capacity Planning, Compatibility.

Here are the steps for node replacement

1. Find the faulty node in Nodes and click Replace Host.
2. Confirm that the configuration of the new node is not lower than the original
faulty node, and after installing the aSV software correctly, check the I am
ready checkbox and click Next.
3. Select the newly discovered node, click Next, and replace the node after
adding it to the cluster.
4. Configure the network, select the storage communication port, and
configure the communication network port IP.
5. Confirm the configuration: choose whether to refer to the disk configuration
mode of the old host, check I am sure I want to replace the physical host,
and click Finish.
6. When the detection is passed, click Confirm, you can see the progress of
the host replacement in the task center and wait for the host replacement
to complete.
7. After the data rebuilding is completed, perform a Health check to confirm
that the platform is running.

best practice is to always have an backup before replacing any node.

Cluster IP

similar or higher number of  HDD and sizes

Ensure you have a backup of all critical data.
Safely shut down the virtual machines (VMs) running on the node to be replaced.
Remove the node from the cluster.

should be on Same Platform
and
the storage should be matched

OS version and hardware equal.
do not remove old node before add new node to replace.

if Node-C is broken, have to be remove away from Cluster-A. By right before Node-C was broken, the data