This has been built into photoshop and illustrator for as long as I can remember, at least using versions back to version 10 of illustrator and 4 for photoshop when I was just a teenage computer nerd in the 90's, but I don't remember using it much over the years at all. However it is actually very useful when you want what I would describe as secondary views and also a way to pan around the workspace without needing the pan/hand tool selected,... here I have made a quick explanation and showing the "Navigator" window within Illustrator. This should help you to begin with I think this is what you are looking for... like a zoomed-in working area to adjust things and especially with text and design balance and layout, centering / visual weight etc, it can help to have that zoomed-out distance-view as well at the same time instead of going back and forth with the zoom-wheel and/or zoom keys, which I think is more of my tendency. Especially with T-shirt design and others where your intended viewing-distance or audience may differ, so the needs of "seeing" your work area in any zoom-size you want while still working within a zoomed window is basically this navigator panel. Go to Window>Navigator, as you see in the image attached. I will have to try making myself use the navigator more often, sometimes there are hundreds of little tools just beneath the surface in these programs and if we don't build the habits of using them we don't even remember the features exist. Hope this helps. Also, wasn't that a strange 90's movie, The Navigator? >Edit: I rambled more than you did, and also the movie is called "Flight of the Navigator" and from 1986, I was only 5. lol
https://www.youtube.com/watch?v=gVebPEYiq2o