I am using a drop down menu to change a line of text but, I can't alter the styling of the text without altering the entire line. I only need to change one or two words of the line with my drop down so is there a way to make it only change the words in a selected range?
I normally just have multiple versions of the text layer and use the drop down to toggle their opacity but I'd like to get this on one layer if possible.
Long and short: No. This is a known issue/ limitation of text style expressions. As soon as you change the source text with an expression, the source formatting is lost and only the style of the first letter is used. Stick with splitting layers.