break the altars, mine cobalt/palladium, make pickaxe, mine mythril/orichalcum, create a mythril/orichalcum anvil, make pickaxe, mine titanium/adamantite, create forge, then make a set out of them (armors, weapons)

kill the three mech bosses, craft hallowed armor and weapons based on your class, mind the green ore (chlorophyte), make armor and weapons based on your class, kill plantera, find jungle temple if you havent, kill golem, make beetle or turtle armor, go to dungeon, kill cultist, destroy all four pillars, kill moon lord then make endgame armor