I'm not sure if this is a possibility for you, but you could connect to one AAD, and setup AzureCP for that AAD. Then add the users from the other AADs as B2B users in the AAD that you connected to SharePoint. It is not the best solution as new users in the "Other" AADs would have to be constantly added as B2B users.
The problem is the value you have in this variable accResponsible. User field in SharePoint list cannot be update using a var value, we need a SP.FieldUserValue to put it into the list.
I find answer here using the person name instead the id is more easy than find user id if you don't have it.
This is not possible from a People Picker perspective (I filed a DCR on this and it was declined by the product group years ago).
You'll have to find another way to deal with this, such as use a different identity storage (e.g. AD LDS) for specific users or move the users into the same OU/sub OU structure.