Shaper of Worlds
Absolutely one of the options, yeah! Ancient Occult Knowledge hidden in some Dungeon because it couldn't be Destroyed. Full on "Book of the Dead" from the Mummy (1999) or Akivasha from Kull the Conqueror. Vestiges of bygone eras and Unaussprechlichen Kulten!Maybe the different patrons could be ancient Sorcerers who fell to corruption and became something like an Archfey or Fiend etc? Then the warlock travels and finds these unique masters, who teach them very specific occult lore, making them different than wizards who instead rely on their own studies and the grimoires in which they are contained.
But also still have actual Fiends and stuff around if someone wants to actively make a pact standard D&D style 'cause that also fits into the Sword and Sorcery Milieu.