Man, I have to get in on this.
I think that one-on-one, assuming Batman is the aggressor, the only people he'd have trouble with are Thor, the Hulk, MCU!Vision, and Scarlet Witch.
Captain America, Hawkeye and Black Widow are all close enough to human that Batman would be on par with them in hand-to-hand. Hawkeye is essentially Green Arrow; Black Widow is just a really good spy. Captain America is an iffy one, because in the comics he's just peak human with an indestructible shield, but in the movies he's explicitly superhuman. That said, Batman has taken on stronger guys before (Killer Croc, Grundy) so it'd be a little way on either side.
Iron Man is kind of a weird one. Batman has built mech suits and power armour before; I think in the fairly recent Endgame arc, he pulls out a truck-sized Bat-Mech and uses it to beat up Wonder Woman, who's a Superman-level heavy hitter. And the thing is, when you think about it the Iron Man suit is not actually that well-designed. Stark puts his power source smack-bang in the middle of his chest, doesn't even bother to armour it. He uses his palm repulsors as his primary weapon despite the fact that it's actually pretty hard to aim at something with your palm; he could just as easily put them on the forearm and make it a lot easier to hit people. Most of his advantages come from the fact that no-one else has an Iron Man suit, or if they do, it's based on his tech but a generation behind. And he relies on the tech too much. In Civil War, as soon as Captain America is in punching range he completely outclasses the guy in the billion-dollar warsuit who never learned how to box. If Captain America could do it bare-handed, Batman could do it in a TDKR-style exoskeleton.
Then you get to the fun ones:
Against Thor, I don't think Batman would have a chance. Thor is essentially Superman but with no kryptonite. It'd be the first two minutes of their fight in BvS, repeated until Thor got bored and left. It's even worse in the comics, where Mjolnir is literally a reality warper.
Hulk is a funny one! Obviously, no, Batman would not be able to beat the Hulk in hand-to-hand. In the comics, no-one can beat the Hulk hand-to-hand. In the MCU, Tony managed it with the Hulkbuster, but that was a suit designed with Banner's own input and designed from the ground-up to wear the Hulk down. And even then, it's implied that the reason the Hulk let his guard down was because Scarlet Witch's mind control wore off.
Now bear with me here, because I still think Batman has a chance against MCU Hulk: he just has to use that magical tetrodotoxin D that Fury uses to fake his death. It was literally designed by Banner to suppress a Hulk-out. So long as he can get to Banner before he...hulks, Batman could just jab that in him, then let Banner fall into a coma for however long.
MCU!Vision is even more of a Superman-expy than Thor is, being vastly more powerful than his comics version (who's just a robot meat shield). Batman would have the same problem he has with Thor. Except even worse, because while Thor is kinda dumb and could theoretically be tricked, Vision is some super-Jarvis AI with an infinity gem for a brain. Maybe he'd be vulnerable to malware? I don't know how Batman would out-hack a super-AI. Batman's not even some excellent hacker; he just has the advantage of owning the company who everyone contracts to build their security system. You'd have to be Brainiac to hack the Vision.
Scarlet Witch is the last one. In the comics she's literally a reality warper, making her incredibly hard to deal with. In the movies she's toned down, but still powerful enough telekinetically to push the Vision down six stories. Batman would basically have to take her out with some kind of tranquilizer before she knew he was there.
Oh shit! I forgot Falcon. Well, he's...he's Falcon. He flies, and he shoots guns, and has a drone thingy...not that he isn't badass, he's plenty badass, but I think Batman could take him down. He's had to deal with fliers before (Man-Bat).
Edit: All the boring people who just say "batman can beat anyone if he has prep, hands down" kind of miss the whole appeal of putting Batman in a versus fight. The whole thing about Batman is that he's the perpetual underdog of the Justice League. They've got heat vision and magic lassos and power rings and the Speed Force; he has a bat costume and a utility belt. When Batman beats up one of his peers - in whatever scenario - it's supposed to be exceptional, not routine.
I mean TDKR - the comic that started the whole Batman-vs-Whoever trend - makes it a pretty clear plot point that Batman was gonna lose. He "won" by pussing out and having a heart attack before Superman inevitably threw off the kryptonite and went back to thrashing him senseless. I don't think "has a heart attack and makes the other guy feel super guilty" is the definition of victory.
