We want router 1 to be the primary router that all incoming traffic goes over and router 2 to be the backup.
How do I manipulate the prefixes I advertise to the ISP & INX’s so that router 2 is seen as futher away than router 1 so that router 1 takes all traffic unless it fails.
I think what you want is AS path prepending. You can add (prepend) your own ASN to your advertisement one or more times to make it appear to particular upstream connections that you are “further away.” In reality this is more of a suggestion, and you will get some traffic that comes over the “backup” connection, especially traffic originating from the directly adjacent AS. You can use outbound route maps to prepend your AS. Also, consider using BGP communities from your ISPs to prepend their ASN a few times to the path. Only certain ISPs provide communities and/or communities with this function.