This is the actual deal. It's been approved by the US, UN, and Qatar as a mediator. According to the US, it came from Israel, but there's apparently a little civil war going on in Israel's government about whether to "agree" to it or not. It seems likely to me that the terms were simply dictated to a mostly-unwilling Israeli government, then announced (by the US) "on behalf of Israel," and now they're pouting about it but also don't want to say out loud to their sugar daddy "fuck you I don't want to," because then we might stop arming them so comprehensively and vetoing things for them at the UN, and so they're stuck.
Hamas's proposed changes are not public, so it's impossible to say how big a deal they are or how necessary. I tend to blame Israel in general because they are so clearly acting in bad faith and also they're the ones killing all these innocent people, but... I also have to say that Blinken's statement makes some sense to me.
It would have been very easy for Hamas to simply agree to the deal on the table, and if Israel wants to reject it, or “accept” it but just continue the war immediately under some paper thin excuse (both of which seem highly likely), then at least there's not this weird confusion about whose fault that is. It's hard to come up with an explanation for Hamas wanting changes and fucking the whole thing up that doesn't involve blaming them for the inevitable results of that decision at least partly. To me as an unqualified observer person.