New mac studio Mouse issues

We just purchased a mac Studio and are having trouble getting a mouse to work properly. We have tried a logic tech wireless, a logic tech usb mouse and a Tecknet wireless mouse. All work to a certain point. You can move the cursor but when you "click" on a menu, the menu under the cursor is not the menu selected. Example, in Mail, You click on "file" and you get the drop down menu for "edit" . Or you "click' on an open window and some other window comes up or goes away. We are using a Dell 31.5 ultra sharp monitor and a USB C cable to connect.

Any Ideas would be great. Thank you