That’s the Halacha. Matza is considered הנאה לגוף even if you don’t like it. (בלע מצה יצה מרור לא יצה)
Of course you are supposed to have kavanah the question is whether you can be yotzeh without it.
The entire drinking is one hemshech of kiyum hamitzva. There isn’t one gulp that takes you over the top.
The lomdus isn’t too complicated, if you need help ask the Lakewood bochrim that come to you’re shabbos meal.
(Btw the Ran is in RH daf 7)