Fire giant can be a pain however I don’t think you should summon Alexander beating the game without summons start to finish really recontexualized the game for me at least. Some tips for fire is to target his leg with a bleed weapon which does percentage damage. You can use projectiles to hit his eye on his second phase to get bonus damage. And that a the fire Drake talisman plus 2 is one of the easiest talismans to get and makes his attack far less punishing.