Why not set label with in dataview properties to 4 or 5?
If only for a selection of input widgets, then I would add a layout grid with 2 columns with required distribution. Add text widget with semi-bold style in first column and input widget in 2nd w/o label
I prefer this over custom styling, as these are more hidden and less maintainable out of the box
I think it can be adjusted through styling by creating your own class or using css ladder as you used already.
Can you try an add !important to your styles? This won’t let the other col class overwrite your style.
for example:
width: 200px !important;
Let me know if it works.