Thanks for getting back with the variable logs. Though it think I know whats going on here. I may have initially misinterpreted your issue, the
Octopus.Aciton.MaxParallelism variable is responsible for how many machines/targets each step will run on in parallel. It looks like you are trying to specify how many deployment steps should be executed by octopus in parallel.
To configure this, you will need to put your steps into child steps. This have Octopus run the child steps in batches.
The documentation I linked to has a lot more information on this.
Let me know if you have any thoughts here, or if I have misinterpreted your issue still.