There are some questions that you have to answer. First you need to define your requirements on data separation. In your case I guess there's no need to physically separate them.
Then next question is on your requirements on configuration separation and autonomy of your teams to adjust the configuration. If you have only 1 team managing all stages and apps, you should rather have 1 environment as it's easier to manage. Thank here also about scale so you don't have more than 25k OneAgents connected to one or other limitations.
Management zones can help you to organize the data so you take a look precisely on what are you interested in.