One of the things that's annoying me about the bosses is that despite the game and fanboys telling me I should experiment, there ends up being only one practical way to win and it involved equipping two of the same weapons to stagger it (machine guns or pulse guns, depending on the boss). This is exactly like Elden Ring where it was- so many different ways to play, except really just use mimic tear and bleed.
Between what I've seen other people beat these bosses with, as well as my own personal experience... yeah, naw, that's not the only "practical" way to beat these bosses. Those are good and possibly
efficient ways to beat them, but rarely did I ever beat a boss dual wielding a weapon type. My builds tended to focus on an array of options that worked for me through, as you say the "fanboys" suggest... experimentation. Finding what I like and what works for the AC I'm building around.
A lot of past AC games were easy enough (even on hard mode missions) that I could build 1 AC, maybe swap a few weapons out as needed, but otherwise could keep it the same over most of the game. AC6 put me in positions where I actually felt compelled to have 4-6 builds at the ready for different purposes, and there was rarely a one-size-fits-all AC I could apply to a mission. Doing so helped even the odds when I was put on the disadvantage.
I don't hate the big bosses but the kind of challenge they pose is wildly at odds with the kind of challenge posed by the rest of the levels they're in, which is how I ended up with the aforementioned pair of primary ACs, with one set up to traverse levels and one solely to fight bosses (other than ACs which my level traverser could fight just fine)
This is the takeaway I got from the game very early on. By the end of the game I had an AC for lengthy missions and ease of use, a "general purpose" AC for shorter missions and a wide range of attack options for whatever could be thrown at me (but it lacked firepower and ability to survive high pressure skirmishes), a reverse joint lightweight AC, an AC vs AC build, and a tank AC. All of them got extensive use over the course of the game.
It's a very different kind of Armored Core compared to what we had before. I welcome the changes personally, cause it makes sense for you to not be able to just fly by with one or two AC builds that let you plow through every situation without issue. That defeats the purpose of the whole thing... building your AC with tons of available options.
Is the game frustrating? Oh yeah, for sure, but I guess it depends what you have the patience for. I had the patience to persevere, some people didn't, and that's totally fine