I`m not sure it`s bad stamina. He makes many runs and is playing at a high speed. It`s normal for a player who is playing like that to take a breather from time to time to recuperate.
No matter how fit you are, your body needs to recover from high intensity bursts or else you`ll bonk and be useless.
He also stayed wide and constantly stretched our width. Made runs behind the defense too. Cutting inside like Messi or going wide for a cross were a part of his game. He was pretty much a complete winger, more so than the guys you mentioned...
In the start he maybe was a true winger, but last two seasons he was drifting more and more into the middle. I think it started back when messi was out for 2-3 months in autumn 2015? And neymar took over as the leading player influencing the whole game and making the whole world stunned and winning a third place in the b'dor in the process. After that Messi came back as the "whole game"-influencer. In my eyes that was the starting point of the player he is today, and also the starting point of when he realized that he couldn't out fold his full potential here, because there wasn't enough place for both of them. Also, thats why many thought we would be better off without Neymar, he was too good to just be a normal winger, and he knew it, and wanted more influence but that made our team crack since our attack got to messy and unorganized with two 10´s. Well, anyway - all in all, i wouldn't call Neymars Barca stint as true winger, his most dominant years and last years, he was a messi-like player.
(off-topic, but i always wished that he could have just stayed playing on the wing, and being fine only being number 2 here, and taking the torch when Messi found it reasonable to step down, if thats how it would have been, i think neymar by now would have been our number 1 and winning b'dors but yeah who knows) Edit: And our chl-record would have been way better. edit2: Messi would have won 2-3 more or so, and nobody would have had a problem that Neymar would win 'em now.