[FROG] Dual Core Design

Trying to make sure I have the design down. We have 2 cores and 2 upstream connections. We also have a cross connect to an IX off 1 core. What would be the best way to configure iBGP between the cores so that we would gain the benefit of the IX from both cores and concurrent/failover usage from both upstream providers. Both upstream providers are the same speed and we advertise our networks to both in a multihomed scenario. We may be adding a 3rd core/upstream provider in the future. Core1 connects to ISP1 (full table) and IX Core2 connects to ISP2 (full table) All edge routers have an iBGP connection to both core routers and receive default routes only. Debian 10 FRR 7.2 Thanks Travis