this sums up exactly why I loved that part of the "fight" so much
because it was so different from what triggered all the other final part of the showdown. In every other part, negotiation with the villain has never been possible, for some reason or another. Dio didn't want anything other than killing the Joestars for standing in his way, Kars sought humanity's extinction, Kira and Diavlo needed to kill to keep their secrets, and Pucci sought to reset the universe. NONE of those goals could reach a mid point which would be considered acceptable to both parties, and honestly neither party even had the leverage to make negotiating seem like a mutually beneficial option
but this is where Valentine and Johnny are a bit different. Because while we as the reader know there was absolutely no way Valentine was going to follow through with his end, Johnny didn't have any massive reasons to think that. After all, Valentine didn't seek their death specifically. They'd just been poking their noses in places they probably shouldn't have been. They have zero personal stakes in Valentine's plans and by all means could theoretically walk away from this without any issue
And Johnny had been absolutely ready to risk it. He was completely 100% ready for Valentine to actually be The Good Guy With Good Intentions, not giving a shit that it meant he would've been The Bad Guy of this particular story
And when he did eventually beat Valentine.......
Just because Valentine lost doesn't mean Johnny won
Because Johnny lost. He lost a lot. Every ally he and Gyro made together was dead and gone with the exception of Lucy and Mr.Steel, Gyro himself, several portions of his body. Yes he got his legs back, but like he says it felt anticlimactic. Not as dramatic or as world shattering as he envisioned it being
Winning against Valentine was neither happy or satisfactory. It was simply all he could do to prevent loosing anything else.
Personally, it's in my top three moments I can't WAIT to see animated for SBR, especially for how the voice actors pull it off