Permission on folder in a document library

Hello,

I need this configuration; I created a subsite and inside this a list: with this list, I create every time a document library that is a project inside my company; every document library has two folders, one for technician documentation, the other for sales docs.

I need to have two distinct types of permission group for the folders: the technician can see theier folders, the sales can have access to both folders.

I used power automate to try to make some automation on it; first, I create 2 security groups under AAD and make it visible under my subsite that is something like https://mytenant.sharepoint.com/commesse ; then, I broke the inheritance with the parent and give the owner of the subsite to the account that also run the flow; every time I create a document library, I assign the 2 groups on that library and then assign to technician folder the security technician group and the sales group while assign the sales group alone to the sales folder.

All works, but when, inside a folder, I try to create a rule to send an email to a user when a file is created (with the menù inside the folder, Automate->Rules->Manage rules->Create a rule) I obtain the error

We couldn't create your rule; please try again.

I found this support document Create a rule to automate a list or library - Microsoft Support where there is clear that the user must have edit permission, an my users inside the security groups have those permissions?

Where am I wrong?