I am surprised by a DHCP client to be automatically attached to an Ethernet interface - I can only imagine this to be done by the mysterious
detect-internet functionality, but my quick test did not confirm that. So maybe it is a misunderstanding and what you actually wanted to say was that the
route was added automatically once you had manually attached a DHCP client to
ether2 in order to get an address from the VSAT modem?
If the DHCP client has indeed been added dynamically, set all the interface lists under
/interface internet-detect to
none to see whether the dynamically added DHCP client disappears and you'll be able to add one manually, configured the way you need.
Once you have a manually added DHCP client attached to
ether2, set
add-default-route=no on that
/ip dhcp-client row or, maybe even better, just set
default-route-distance=5 there, as you only want to use the VSAT link as a backup I suppose (i.e. not for load distribution). If my assumption is correct, it is enough to monitor the transparency of the primary WAN (via ether1) using the recursive next-hop search as described
here - since you have no further backup anyway, there is no action left to take if the VSAT fails, so there's no point in monitoring its transparency.
If it still doesn't work and you need further advice, instead of posting a few screenshots, follow the hint in my automatic signature right below.
