Thank you for the feedback. I didn't really think about my input choices and it is true it should at least have been possible to cancel build mode by pressing the building buttons or other method so that it could be played with only mouse which was kind of the focus sorry about that. And you can "delete" buildings by selecting them while holding down left control which works for blueprints as well. You will get the resources spent on those buildings back but the workers need to deconstruct it.