ECMP - does it work like multi-wan loadbalancing?

[JayST]

our service provider wants us to use two gateways and says they have been setup to require our router/fw to do Equal cost routing (ECMP) to those two gateways (two different subnets).

I could not specifically find information about opnsense and ECMP. But i did find the multi-wan documentation.
https://wiki.opnsense.org/manual/multiwan.html

Can i implement a ECMP equivalent with multi-wan load balancing using same tier for both gateways in the gateway group on the opnsense firewall?