Maximum number of processes, stages, and steps:
To ensure acceptable performance and the usability of the user interface, there are some limitations you need to be aware of when you plan to use business process flows:
Multi-entity processes can contain no more than five entities.
There can be no more than 10 activated business process flow processes per entity.
Each process can contain no more than 30 stages.
Reference:
https://docs.microsoft.com/en-us/power-automate/business-process-flows-overview