This is a common criticism of the arc and I get it, but I personally didn't have any issue with it. I have a different major issue with Moro arc's ending lol, but I don't know if that's covered in the volumes you got so I'll keep my mouth shut on that front. I will however give my perspective on the Goku thing.
I think the biggest problem with it is that it's a narrative repeat (not one I minded since they set it up earlier in the arc), but I don't really think Goku was being stupid there. Selfish and reckless? Absolutely. Stupid? Not so much. Is there a distinction there that matters? Probably not to most, but to me.
For starters, sparing enemies has gone over incredibly well for Goku in the past, Cell's not the only experience he has to pull from. Piccolo and Vegeta work wonders for him, and the first time with Frieza didn't backfire in any way either. & the Moro case situation is actually closer to that. Goku gains control over a powerful new transformation and decimated his opponent, clearly out-classing them. Goku didn't mop the floor with Cell, they were seemingly evenly-matched but Goku knew he was weaker than Cell and believed in his son too much.
The problem with Cell was Gohan, when Goku told Gohan to finish Cell off, Gohan brushed him off saying he was going to make him suffer more. Compare that to the Moro situation, when Whis tells Goku to finish him off, Goku immediately goes for the killing blow, he just didn't get it off before Moro did the thing (I don't wanna spoil that). That's learning a lesson from Cell, listen to the wiser fighters when they tell you to finish things.
Also, you mention over-trusting, but I don't believe for one second that Goku actually believed Moro would keep his words on the senzu bean offer. When Moro does the hand or the end thing, Goku is shown clearly shocked by those actions, but when Moro attacks him after eating the bean, Goku doesn't even react. He totally did that to show Moro how out-classed he was, as a manipulation tactic to hopefully get him to agree. And when he says no again, Goku does go in for the kill (though gets distracted fairly easily by a simple question).
BUT
The main reason I didn't have an issue with it is the alternative was Goku stomping Moro and ending the arc with an easy victory. They spent so much time on Vegeta's character arc, I would've hated if all that amounted too was Vegeta gets bodied so Goku can save the day again. This way Vegeta was able to use his power to play an instrumental part in Moro's defeat, as well the other helper. Reading monthly, I was more worried about this all just defaulting to Goku does everything, so I was relieved when I saw they gave an opportunity for Vegeta to shine instead.
