Purge tool use in production environment

Hello,

I'm starting a project that requires the execution of many process instances, and I want to establish a purge plan, from the beginning

I have to provide to my users 24x24 7x7 server availability.

I want to automatize the purge to happen regularly in order to have a "light" database. I don't want to start it manually.

Here you are my questions:

• From the documentation https://documentation.bonitasoft.com/bonita/2021.1/purge-tool : "Bonita runtime environment should be shut down when running this tool, i.e. Bonita server should be stopped."
  The word "should" is used instead of "must". What are the issues we could encounter if we don't stop the server? I guess that some lock can be created in some tables during the purge activity, so the system could be slower. Any other major issues?
• I want to purge all the process instances older than a certain date, but the process Id is mandatory. Why the "remove all process instances older than a certain date" use case has not been considered? I guess that there is a reason.
  Without that. I have to write a java program to read all the process definition Id, and then loop and execute the purge for every process Id. Not very practical.
  I see there's the way to get the list of processes (executing the purge without the process parameter), but this list is passed together with some description. Potentially I could parse it, but I guess it's not intended for the use I have in mind.

Thank you in advance!