Sierra to Sonoma

We recently upgraded 2 Sierra based iMacs to one new Sonoma Mac. We each have an account and we both have Admin rights. We've had ongoing problems creating new folders under our personal user folders and problems with copy and paste. We can copy fine but paste? will not do it. We encounter no system messages but he two small dots above the name of the target folder don't appear. When we do "get file info" of the target folder, every one has read/write rights

The folders problem is in their creation. We see either '"Alan" can't be modified or deleted because it's required by the macOS. or "The operation cannot be completed because you don't have the necessary permissions.