I could be wrong, but I'm guessing Starfleet isn't so much more heavily militarized as Federation society is edging towards a panopticon in the name of public safety. I mean, militarily speaking the Federation probably still reigns supreme, but asymmetric actions are really hard to deal with via something like starships, causing paranoia to rise
To shift gears, this also makes me realize why Lower Decks decided to set itself only a year after Nemesis. The sort of silly TNG-lite stories they're trying to tell would be entirely out of place in a post-Utopia Planetia setting.
Oh, and I think they probably should have shifted the body count up a bit higher, to be honest. I mean, considering the Federation has a population many orders of magnitude above the U.S., even an initial report of 3,000 dead is more like 30 dead to us. It's a tragedy, but not the defining tragedy of a generation. Hell, there are enough colonies out there I expect at least one is entirely lost every decade or so.