I think the issue might be how you define "more work space". A monitor of the same size but higher resolution only gives you more work space if you're happy working with smaller icons and text. Otherwise you'll end up scaling
everything and you'll end up with the same amount of work space with finer detail. If you're already working with the smallest icons and texts you think you're comfortable with, the only way to get more work space is to increase the size as well as the resolution.
What's interesting though, is how quickly you can get used to higher resolutions on the same size screen. I used to think going much higher than 1366x768 on a 13" - 14" laptop would be excessive, but I got a 1080p 14" laptop in my current post and I've already got used to the increased pixel pitch and smaller UI elements, without relying on scaling. I think the only way you could be sure i9f a 4k panel would work for you would be to use one for a few weeks and see how you get on ... probably not a very practical option though