BGP route-map placement/basic route question

Summary: Where best to place route maps from this diagram? Core needs static routes to reach external?

https://imgur.com/a/LLiur

Currently following this guide: https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13762-40.html#anc15

Load Sharing When Multihomed to Two ISPs Through Multiple Local Routers

edit-1: Feeling that if I deny traffic/configure route maps on the Edge with route maps that packets will start to get drooped, as the traffic would have already left the Core-1 router.

Currently have a BGP network as seen below, the CORE-1 needs default routes currently to both edge loopbacks - 10.10.12.5 and 10.10.12.6 so that full connectivity works. Although these can be changed from default to spesfic routes, I would like to keep them as default routes, with route maps deciding which way spsesfic traffic goes.

Also for your information the core router is just running OSPF and not BGP.

Thank you very much, I can provide more details if required. Hopefully I was clear enough!