I am so glad you posted this question. I realized today that I am having a similar problem.
I can manage (sometimes) with a regular length sweater/ top -- to have a bit of the shirt-tail peek out.
Where I'm struggling is with the cropped version -- where more shirt is supposed to show.
The cropped for regular people sweaters actually DON'T work on me -- either as intended, or any which way. Because the proportion is wrong. They are still cropped on me...just not AS cropped. So they come to my hipbone, vs. my natural waist. And even though I am an hourglass/ rectangle, I have enough hip that tops poof out unattractively if the sweater ends just there -- plus the overall proportions look weird. Now I know why I struggle with this.
I had better luck in the summer with a Zara boxy cropped sweater that had side slits, paired with a longer-than-average top. So far, I have not been able to reproduce the effect with my fall// winter sweaters and shirts, despite deliberately purchasing a few different cropped options of knits.
I think your outfit actually looks good as is -- there is a bit of the plaid peeking out and the whole effect is proportional and attractive. But I know what you mean -- you would like to showcase the shirt a bit more.