To address some of this, I would say that the reason HERO seem complacent is because the monster threat wasn't as bad decades ago. It only started ramping up in the current decade, according to Xanthe and Dexter. So with 3 Level 5s and dozen or so Level 4s, it would've been a cakewalk for them in those 80 or so years that went by. They likely didn't start feeling pressure until Zack and his team got took out. But with Deus, that problem was removed again.
When it's really put out there, there's only 12 known Level 5 Superhumans in HERO. Compare that to possibly millions of C and B Rank monsters, thousands of A- Rank Monsters and possibly hundreds of S-Class Monsters. Even with Deus, they're still going to struggle and that's without Apostles getting in on the fun.
I will say that I don't think they're being totally carefree though. They're always being deployed. They're actively researching at HERO and trying to recruit new people. This is needed because like I showed above, they're vastly outnumbered. It might seem like they're not focused on where it matters but they are, within their capability.
People like the 5 Captains can go long periods without rest. They're used to it but the reason you see people like Lexi, Nico and Clark complain is because they haven't been doing it for more than 2 decades. Lexi was a normal human 5 years ago and now she has to stay up for days fighting non-stop. Without new recruits, breaks and more human related activities, a lot of them are going to lose their minds. It might not seem like a big deal when faced with an extinction level event but it matters. Their powers aren't infinite after all. Eventually, they'll all need to rest.
So, for me, I think they're doing enough but they're being stretched thin to where it seems like they're not doing enough in other categories. That said, nothing they do will stop the Monsters if they actually just decided to destroy the earth flat out. Not even Deus time shenanigans would be able stop the Time Apostle from blocking his abilities, or the 6th from completely destroying Nico. With those two gone, HERO is fucked and you likely wouldn't even need the Apostles to accomplish it really.
For your 1st point. I still think Tiffany had a hand in that whole thing. Even after it, she still seems to be up to no good.
You 2nd Point. I agree, mostly. Xanthe is only human. He would naturally lack the insight of the monster stuff because of it. For him it would be unproven theories, especially for the Apostle corpses, until recently.
Point 3. I agree with this as well.
Point 4. I agree again but don't you dare insult Lexi
. Her and Clark are being deployed everyday, of course she's going to complain when she can't even rest or get sleep for days. Unlike Nico, who chills on a beach, she has to actually fight monsters and immediately go to the next afterwards. As for Clark, he's a weeb.
Overall, I don't see much of a problem with HERO's behavior. They likely don't know how bad it's going to really get and there's a possibility that even Deus and Zack can't see what's potentially coming. They can only work with what they know currently. From that perspective, it likely doesn't seem as dire for them. They stopped Ella and the monsters slowed down. For them, that's a win and now they can focus back on building up their resources again while they have the chance.
