For the Mesopotamian deities, maybe draw from the "Chaldean" astrologer-priests of Babylon. They worship the seven planets: Sun (Shamash) and Moon (Sin), plus Mercury (Nabu), Venus (Ishtar), Mars (Nergal), Jupiter (Marduk), and Saturn (Ninurta). These gods are impersonal, more like abstract principles of a clock-like universe. The planets are omens revealing the cosmic processes. The Sun is daily and annual properties, and Saturn properties stretch out across three decades.
For D&D, the planets and astrology are already in place, perhaps give them names sounding as if Sumerian, Akkadian, or Aramaic. While the horoscopes are thought to be"inescapable", magic can enhance good ones and contain bad ones. The magic is a divine-arcane blend of theurgy. The horoscopes only refer to nations and geographic regions, not individuals (unless involving the leader of a nation).