I just did a quick bing chat search (“does DRI_PRIME work on systems without a cpu with integrated graphics?”) and it says it will work. I can’t check for you because my CPUs all have graphics.
I CAN tell you that some motherboards will support it (my ASUS does) and some don’t (my MSI).
BTW, I’m talking about Linux. If you’re using Windows, there’s a whole series of hoops you have to jump through. LTT did a video a while back.