I get it’s very arable but

I'll get to the other value, but you have to understand that for most of human history, really until just about 100 years ago, capacity for food production was one of the most valuable things a place could provide. The development of the Haber-Bosch Process is possibly the most important unsung event of the 20th Century. Roughly half of the modern world is supported by synthetic fertilizers. Prior to that invention, the quality of arable land was significantly more important to being able to support a population, and regions that could produce a surplus were invaluable to imperial conquerors who sought to unite regions with other economic value, but insufficient agriculture. If you can import food, or simply appropriate and redistribute through taxation, then you can support a much larger population in otherwise infertile regions.

outside of that I don’t see that much value in it

In antiquity, we can roughly equate modern Iraq with Mesopotamia, and the north in particular to "Assyria" up to the 7th Century CE. The region in question is an invaluable crossroads of geography. While southern Iraq (or southern Mesopotamia in antiquity terms) is somewhat more fertile thanks to the proximity of the Tigris and Euphrates, the north is where those two rivers begin to connect to other regions. The Tigris extends north into Taurus Mountains, while the Euphrates continues westward into Syria with a westmost point relatively near the Mediterranean. Those connections made northern Mesopotamia a hub of trade as early as 2300 BCE. One of the first imperial conquests of the region, and arguably the first empire ever, came with Sargon of Akkad, who followed the course of the rivers when expanding to the north.

Some of the earliest Assyrian records aren't even from Assyria at all, but from outposts called karum in Central Anatolia. Rather than extensions of imperialist ambitions, these were trading towns that connected the mineral wealth of Anatolia (roughly modern Turkey) with the food and luxury goods of Mesopotamia.

This region is also connected to the east, through the mountain passes of the northern Zagros mountains, which led directly to the various kingdoms like Urartu and Armenia that formed around Lake Van and the powers that ruled northwestern Iran. Another very early example of imperialism in the region flowed directly from the economic value of these mountain passes, which connected to the tin trade from the Iranian mountains and beyond in Central Asia. In the 18th Century BCE, an alliance of Hammurabi's Babylon, the Syrian kingdom of Mari, and Elam (the most powerful state of the time based in southern Iran), invaded the northern Mesopotamian kingdom of Eshnunna. Babylon and Elam intended to carve off territory, but Mari in particular is noted for aiding the effort primarily to gain more direct access to tin, without Eshnunnan taxes. Ultimately, the alliance devolved into backstabbing and Hammurabi came out on top, with Babylon conquering most of Elam, and all of Eshnunna and Mari for a time.

That brings me to the final component that made northern Mesopotamia/Iraq so important to 4000 years worth of empires: It is right in the middle of everything else. I've partially addressed the economic implications of this already. Assyria's role as an artery of trade didn't die with the Bronze Age tin routes. It continued to act as the primary node between Central Asian trade with Anatolia and the Mediterranean until the Russians firmly controlled the northern route through the Steppe in the 18th Century CE, and even more crucially the overland Silk Road between the Mediterranean and China prior to the Colonial Period in the 16th Century CE.

This centrality also made northern Iraq politically and militarily valuable. It was historically a wealthy lowland plain pinned between mountains on two sides. Those mountains, the Taurus and Zagros, routinely formed stable natural borders for other cultures, and when those cultures became powerful enough to build up their own empires, that plain became an obvious target. When powerful states emerged on either side of the mountains, it became a battleground as both sides tried to secure their own borders. That can be seen repeatedly, be it the Assyrians and Hittites, Romans and Parthians, Ottomans and Safavids, or any of the other myriad cultures that have ruled there.