BGP question with MikroTik

Here is scenario. I'm new to BGP. 2 MikroTik routers to handle intervlan routing in HA scenario. 2 draytek routers connecting to vDSL with 4g as backup. I don't want to use vrrp on the MikroTik, I've thought about doing some scripting to disable/re-enable ports. Each MikroTik will have one port...