I dont try to be some sort of elitist, but to be honest, i kill the Moon Lord with my S.D.M.G or the coingun in about 20-25 seconds. I mean yea, if you have not top-notch endgame Gear it might take a while, but over all its just a very easy boss.
Btw its possible to farm for Vortex, Solar, Nebula and Stardust armorsets without fighting against the Moon Lord. Just kill the Piles and leave the map shortly after the DOOM-Message appears, then the Moon Lord doesnt spawn and you can do it again.
I remember the days when i played Monster Hunter Freedom 2 and Unite, Bosses like the "Twin-Tigrex" in "Land of Earthshakes" in G-Mode where pretty impossible to kill, you had one and a half hours to do so and i where unable to, even if my Gear was neat to that point. It was until i made it (dont ask me how) and i played through all G and G+ Quests i saw that back then the Quests where just a joke, no matter how strong the enemie was, when i discovered the White Fatalis Weapon- and Armorset. Its just Gear and experience that makes the difference between easy going and impossible to do.
I made a 20th wave run of the Frost Moon this week on MOBILE. No arena setting, no traps or critter farms, just the ultimate Gear and a modular strategy. Figuring out is the key my friend.
No game in this world is unbeatable, even super mario kaizoo-maps needs to be executed first to be uploadet to the puplic. My passion is to find almost impossible instances and situations in games and play them so many times that it seems to be easy for me, which is of course not.
There are some games for you to look into, so you can understand my point. Look them up on YouTube to get a feeling for what people are capable of.
Super Hexagon (Open Source Version, Dragon-Level, i swear this is insane)
Kaizoo-Trap
Monster Hunter Unite, Kushala Daora in G++ Mode (one hit kill with the best armorset, and he rages like a Venus-Tornado)
Broman's (2-D hit-and-run indie shooter, Speedrun without a single death, just Mindblowing)
Super Mario 64 (the many-world-theory gets executed, this is more complicated then the String-Theory, and a single guy figured it out)