In that instance though its not that you need to do more than the job, its that the job also involves doing multiple things, some of them you might have never d

In that instance though its not that you need to do more than the job, its that the job also involves doing multiple things, some of them you might have never done before, thats totally fine. If doing the job isn't enough, change the job description. In my opinion, just expecting people to do more than their job, even if its a start up, is toxic and exploitative. There are tons of generalists out there, hire one if thats what you need.