Even if you're playing post defense well, Rondo and Sleepy are just bad options to deal with bigger post-up guards.
Everyone looks at height and often Strength, but Strength is relative to Weight. And you have to look at Low Post DIQ...a lot of us believe that, even when you manual the defender, this will have a lot to do with whether or not the opponent gets the most favorable drop-step/post-spin animations.
Payton might be one of the better options to deal with the big guys, without actually having a big guy. I suppose Giannis can work as well, but I don't actually like running him at PG. Shuffling around assignments works, too, and someone like Kawhi could work nicely...but he's not actually necessarily ideal as he's unremarkable in Strength and LP DIQ (the Playoffs Moments, not Playoffs Performance).
I've only played one game versus the new Magic, but had a friend suggest using Amethyst Dave DeBusschere on him. Had worked for this other guy, and I tried it, and Dave DeB, with a +6 Speed/Accel shoe, worked well. He works like Ben Wallace works: guard-like mobility with wing-like speed, but center-like strength and low post D.
I was lazy and just slotted him in at PG and ran my offense through my SG.
Rodman would work well too. But the thing about Dave DeB is that he's a very good shooter and post-up man as well. So you're not sacrificing offense with him the way you sacrifice with Wallace or even Rodman.
I don't know about relative cost, but for defensive purposes, I'd rather have the Diamond Pierce (with +9 Contest shoe) than the 94 OVR Kawhi. Especially for defense against post-up guards/wings.
It's not that he's bad, but he's a defensive liability. He has great post animations and if you want to really work the post, then it makes sense. But I think it needs to be at 4, or at least be prepared for the opponent to try to abuse him in the paint with their 5.
High end teams may have centers at 4, too...i.e. Kareem.
And even at 4, I'm not big on LMA, because I think he's also too easily exploited on D by Stretch 4's. Just pay attention to this and consider if you're actually getting more points with him than someone else...enough to compensate for what he gives up, compared to someone else.
I would rather run Amethyst AD over Diamond LMA, personally.