There's a good article, Do you really understand how your trim works?, that explains how trim works, and in particular how stabiliser trim (what the author call

There's a good article, Do you really understand how your trim works?, that explains how trim works, and in particular how stabiliser trim (what the author calls "trimming tailplane") differs from the trim tab ("conventional trimming") found in smaller planes (that many pilots train with). They operate pretty much the same to first order (for small perturbations), but quite differently for larger deviations from neutral. Bottom line, as you said: You can't overcome bad trim in an airliner by "pulling harder". https://www.skybrary.aero/bookshelf/books/2627.pdf https://www.skybrary.aero/bookshelf/books/2627.pdf