For the two screws that go onto the bracket on the Ender 3 V2 Neo, the size is most likely M3 x 16mm.
I bought the wrong screws, apparently I like doing that, M5 is way too fat. And the shortest ones I have are 30mm.
I measured with calipers, since the internet is mostly useless when searching. But my calipers might not be very accurate, because it was slightly under 3mm, maybe around 2.8mm. The full length, not just the screw part but the head too, was around 17mm. So probably screw part is 16mm. And who knows, maybe I suck at using calipers. Could try my old calipers, but I already put the screw back in. Not sure I still have the old ones anyways.
But I don’t think they make a screw around 2.8mm. What was it 2.87mm? Might need a custom screw to get that size.
Does it even matter that one of the washers is gone from getting melted off? No idea, but might as well have extra screws, you can find the right screws on Amazon. Sorry I’m not allowed to link to the Nazis.