The part you're missing with your idea of putting another router in the middle is that the LAN clients won't know and don't care about the router's next-hop(s). The LAN clients will always talk to router on 192.168.1.1 and the router will decide how and where to forward the packets.
You'll definitely need to get the one WAN device re-numbered off of 192.168.1.1 and probably all of them should be on unique subnets.
From what I know of Mikrotik, I think it'd be much easier to configure on a Ubiquiti EdgeRouter product (not UniFi or UISP). There are also routers from TP-Link, Peplink, and others that specifically market themselves for multi-WAN and may be easier still to understand/configure.
Comments
The part you're missing with your idea of putting another router in the middle is that the LAN clients won't know and don't care about the router's next-hop(s). The LAN clients will always talk to router on 192.168.1.1 and the router will decide how and where to forward the packets.
You'll definitely need to get the one WAN device re-numbered off of 192.168.1.1 and probably all of them should be on unique subnets.
From what I know of Mikrotik, I think it'd be much easier to configure on a Ubiquiti EdgeRouter product (not UniFi or UISP). There are also routers from TP-Link, Peplink, and others that specifically market themselves for multi-WAN and may be easier still to understand/configure.
Oh, and as others mentioned, VRRP or CARP is how you can get high availability for your new routers. Both Mikrotik and EdgeRouters support VRRP.