Using multiple devices with the same IP address … many exemples here in this forum.
This is just one of these : http://forum.mikrotik.com/t/access-multiple-devices-with-same-ip-address/106788/1
General idea is to give each device a unique IP address so you can differentiate [and route] them in your network , and then DST-NAT to that one common IP address the devices have on interface exit.
Select and address them with your unique address. Problem is more complex if your application insists on using that common same IP address, or if they are all on the same ethernet interface.
But for load balancing you can choose the IP address, and connect each Starlink to a separate interface.
Starlink satellite has 16Gbps bandwidth AFAIK (“Each antenna has a limit of 4Gbps, the satellites has 4”). Does the “Starlink for business” terminal combine multiple home Starlink bands? There can be something like 40 dishes in one cell, each getting 180Mbps. It is not because my neighborg added 2 dishes recently, that my speed dropped.