Could not understand the question. Would you mind to elaborate a bit more for our understanding and maybe the solution you are looking for.
If possible you can also share the screenshot for more clarity.
I do not know what the variable will support as a maximum number in the configuration, but having worked with this setting with multiple customers, a practical upper limit seems to be 35-50.
Please bear in mind that the more parallel reports are allowed to run, the more risk there is of impacting overall performance, which can manifest in processing delays.
Gianluca could you share some example of reports where you need to extend those values? It seems like you are running quite a big reports. Maybe there is a way to simplify them.
For example reports like "Metric charts" have been built to reuse the same query across multiple charts - this way database / cache is only queries once, while we render multiple charts showing only selected metrics in each chart.
I can jump on a call with you to analyze your use case in details.