Creating New Windchill Redundant Server

Hello,
We have monolithic Windchill Setup.
Details:
1. One Main Server

2. Replica Server 1
​​​​​​​3. Replica Server 2
4. Database Server 

As failsafe  in runtime, if the main server goes offline due to (hardware issues, OS issue, Network issue, etc) there needs to parallel redundant server.

I have checked below articles about cluster for Windchill.
https://www.ptc.com/en/support/article/CS30922?source=search
https://www.ptc.com/en/support/article/CS436863?source=search

Questions:
What is the first step to move towards cluster or redundant environment?
Is it good idea to have new separate application server and new separate DB server as backup?(These application and DB server needs to have same configuration)
Considering emergency on application and database servers as well, then is cluster a good option?
or is there a other solution that is available for situations like this?