The real game-changer is prepping your skin before the primer - like using a toner or hydrating essence even if you have oily skin, because paradoxically dehydrated skin produces even more sebum to compensate.
Then, instead of putting powder all over at once, really focus on the T-zone with a thicker mattifying powder (like translucent but you use more of it), and keep the rest of your face lighter.
Another little hack too: after your setting spray, wait for it to dry completely for a few minutes before touching your face, and if you use an antibacterial blotting paper during the day, it absorbs without wrecking your makeup like those little tissues do.