What we can do if we will end up having more than 50,000 folders with unique permissions

As per my knowledge on SharePoint Online limits, is that you need to keep the documents with unique permissions below 5,000 for each library/list, but you can open a case with Microsoft to expand this to 50,000.

now in our case we are building a project management system using SharePoint + Power Apps + Power Automate, with the following scenarios:-

1. When someone creates a new Project inside the SharePoint online custom list
2. a Power automate flow will add a Project folder with 5 sub-folders (New, In-Progress, Done, ApprovedByCustomer & Archived) inside a document library
3. each folder will have unique permissions based on the projects stakeholders. for example the Project's field engineers can add files to the New folder while have read-only on the other files, and so on.
4. now the requirement is that even if the Project is closed, the folder permissions should stay the same.

So if we assume that each Project will have 6 folders (1 main folder + 5 sub-folders) which have unique permissions + each project will have around 15 files inside the folder. so at the end each project will have 6 folders with unique permissions. so in our case after creating 8,333 projects (50,000 / 6) the SharePoint will no longer support new projects. is my assumption correct? and can we fix this?

Thanks