Cost effective DR solutions on Azure Cloud

For example, if you have 5 servers

Scenario 1 - All 5 servers are critical.

in this case we will keep 5 servers in the cloud.  We will configure Software agents on premise servers to replicate to 5 cloud servers. When on-premise server fails cloud servers will take over.

We can offer a managed DR solution on cloud.

Scenario 2 - 5 servers 3 are critical and 2 are non-critical

In this scenario we will keep 3 serves as active and for two servers we configure DR in such way it triggers cloud server only when the primary is down.