AD360 High Availability missing functionality

Hi AD360 Team,

The following AD360 documents released/provided by ManageEngine were referred:

To setup HA for AD360:
High˜ Availability Configuration Guide (manageengine.com)

To setup AD360 as Reverse Proxy:
Using AD360 as a reverse proxy server (manageengine.com)
Setting up a reverse proxy for ADSelfService Plus using AD360 (manageengine.com)

After referring the above documents, it's clear that ManageEngine even recommends AD360 as Reverse Proxy must be placed in DMZ.

As best practice and also as a Security measure, the DMZ servers should not be added as members to the existing Active Directory Domain.

So for 2 servers having AD360 installed on them, which are in Workgroup, configuring HA is not possible. Due to the lack of this, this makes it possible to have only 1 server with AD360 server acting as a Reverse Proxy. This also means we end up with a Single point of failure (SPOF)

So if this 1 AD360 server goes down, the rest of the applications integrated in it would be inaccessible.

How is this to be overcome/solved by ManageEngine?