They had Chet guarding Haliburton and SGA guarding Myles
Say what you will about the 90s and the 2000s but, the Big men back then would've feasted on a 6"6 guard playing defense on them.
No they wouldn't have.
Because it wouldn't
just be a 6-6 guard defending them. It would be the 6-6 guard, with multiple help defenders sitting in the pockets on either side of them waiting for them turn. They'd also have to contest with the officiating where the smaller defender would get away with a lot more contact, and if they used even 1/10th of the same physical force to move the smaller defender out of the way, they could be whistled for it, quickly putting themselves in foul trouble.
Furthermore, there's only a remote handful of bigs in NBA history who're good enough to run a high-level, championship offense through the post (even fewer if you put them in today's game), so just inserting any old big man from the past to take advantage of a smaller guard wouldn't result in shyt.
You think a team is winning anything using the likes of Dale Davis to post-up smaller guards?