Your mixer outputs and monitor inputs both use 1/4" TRS. You simply need two balanced cables with male 1/4" TRS connectors on both ends.
An insert cable is for a different purpose entirely and not the correct cable for the job. The difference with an insert cable is that it's wired with one TRS connector on one end, and a couple TS cables on the other. One TS is a send line while the other is a return line. The TRS side is wired with the tip as the send and the ring as the return. This type of cable is intended only for insert points on mixer channels where you're sending the signal to a piece of outboard equipment and then bringing it back in all on one single mixer patch point.
For your mixer output to active monitor inputs, though, you have two balanced cables each going in the same direction, so you just need two balanced patch cables in whatever length you want, one for the left side and the other for the right side, both with 1/4" TRS ends on both ends.