I always intentionally mix and match aspects of different cultures and time periods when worldbuilding. It makes for more unique worlds and allows for in-world people groups that are less stand-ins for a real group and more a confluence of interesting concepts from a variety of them. I don’t want a stereotypical Arabian Nights region for my homebrew setting. I want a matriarchal society of geocentric Aztecs ruled by Caliphs that claim to be descended from the prophetess of the Earth Mother, who use elemental earth magic to terraform their environment and create great monuments to their ancient empire. And their ziggurats have Roman arches, Arabian domes, Japanese pagodas, and stained-glass windows.
In my current setting, the warmongering expansionist empire based on the nomadic peoples of the Eurasian steppe are Aasimar, and they are mainly inspired by the Scythians, but their religion is a mix of Cahokian, Egyptian, Greek, and Scythian influences (they have a bird-headed Sky Father god, chthonic sinister Earth Mother goddess, golden sun lioness hunting goddess, etc). They put the mummies of dead kings in grand kurgans dedicated to their accomplishments. They regularly raid poorly defended cities, monasteries, and caravans. Enemy skulls are taken as trophies and turned into goblets. The monarchs claim descent from the gods and their royal symbol is the gryphon. They also have magic items that can control the weather through nature priests. Their current warrior-queen owns Blackrazor, which she believes gives her the right to conquer the world (based on Attila the Hun and Scythian Sword-Ares).
This world’s equivalent of the Roman Empire is more inspired by the Carthage, the Mandaeans, and modern America, but with a very Sethian Gnostic religion (but with Ahriman, karma, reincarnation, boddhisattvas, afterlife soul pilgrimages, and so on). One of the empire’s successor city states is a semi-theocratic feudal kingdom with Nazi Aasimar extremist groups and Ptolemaic Sorcerer-Kings.
I’ve also got more ideas floating in my head that I haven’t fully developed yet, like an expansionist, colonial Dragon Empire based on Rome, Persia, and Han China. Yuan-Ti Mesopotamian river Vikings. Or the Gnomish Dutch-Venetian-Tenochtitlan merchant republic. Also, Tibetan-Inca Dwarves and Greek-Canaanite angelic Goliaths.
Also this seems relevant: