How to configure two RDS 2012 R2 servers on same subnet.

You have to understand what the connection broker does.  It is a "gatekeeper."  It does not handle users sessions at all. *THAT* is the session host role.  In larger deployments, the connection broker lives on a server that doesn't even act as a session host.  Smaller deployments is where you can get away with cohosting them.

So yes, you'd usually have one connection broker that redirects users to the session host most appropriate for their request.  The connection broker does this by finding out what "collection" the user wants, then load balancing to the server in the collection with the least number of active users.

For that to work, it has to *know* what users are connected to any given server.  And that means that yes, there is one connection broker for multiple servers.

You can set up a second connection broker for high availability, but that requires a back end SQL database and is not trivial to do.  It isn't a matter of just spinning up a second connection broker.

I'm wondering if i messed up on the original server while trying to replicate settings.

In theory I should be able to have identical RDS servers with all roles on the same domain?

No.

Not with all roles anyways. That would negate the purpose of the RDCB role altogether. It'd make licensing so complex that it'd be unmanageable. And even the gateway and web roles would rarely be deployed like that.  And even if you doubled all roles which is.... Insane... You can't have identical settings. They'd actively conflict.

gotcha. so can you point me in the right direction to resources to set this up?

Try Seeing https://nedimmehic.org/2017/01/21/deploying-remote-desktop-services-2016-step-by-step/ which covers most elements.

I got it working, i think.  The question now is how do I force certain users to login to a specific server and not let load balancing pick and choose the server the users login into. the reason being is that i'm installing office365 proplus on one of the servers and don't want the users to be without Office access if the server logs them in to the other server.  Both servers have the default load balancing at 100.