How maximum number of permissions is calculated in SharePoint Online?

Question

Hi Community!

I am currently building an integration between Dynamics 365 and SPO for managing documents.

As I would like to handle custom permissions on folders, I come with few questions after reading Microsoft documentation:

• https://learn.microsoft.com/en-us/office365/servicedescriptions/sharepoint-online-service-description/sharepoint-online-limits#unique-security-scopes-per-list-or-library
• https://learn.microsoft.com/en-us/sharepoint/troubleshoot/lists-and-libraries/error-share-break-inheritance#cause

Then, considering this, I am wondering how the 5'000 recommendation is calculated?

Let's take an example based on this folder structure:

• Account1 (folder inherits permission from library)
  • Opportunity1 (folder with unique permissions)
    • Document1 (inherits permissions from Opportunity1)
    • Document2 (inherits permissions from Opportunity1)
  • Opportunity2 (folder with unique permissions)
    • Document3 (inherits permissions from Opportunity2)
    • Document4 (inherits permissions from Opportunity2)

Do we consider that only 2 items are in the 5'000 recommendation (meaning that I can define 4'998 more items with custom permissions)? Or, because documents are inside folders with unique permission they are taken into account for this recommendation (meaning that I can define 4'994 more items with custom permissions)?

Hope that it's clear and thanks a lot for your help!