The thing is: the USA position of “Maximum pressure, zero concessions” is the same as it’s always been, it’s just this administration have shouted about it as if it’s something they’ve come up with. The Americans have already gone from “What the …?” to “Look what we’ve done!” They’ve been completely wrong-footed on this.
At the moment no-one apart from the North Koreans knows what they hope to gain from this, maybe they themselves don’t, it’s a bit of dangerous brinksmanship on Kim’s part. By all accounts there’s been no state TV announcement about this, there probably won’t be until after the meeting so that the result can be massaged as they see fit. But the inner circle will know and if he gets it wrong the generals might decide enough is enough and get rid.
Militarily the two sides are at stalemate: NK won’t attack because they know they’ll be wiped out in retaliation; the USA won’t attack because civilian casualties in SK would be enormous. There have been joint USA/SK military exercises close to the border for decades. NATO and the Soviet block did the same along the Iron Curtain, basically a lot of expensive posturing.