VRRP - load balancing
When deploying Virtual Router Redundancy Protocol (VRRP) as an FHRP protocol, load balancing must be configured in a manual manner. VRRP does not automatically load balance traffic across all of the available routers.
In order to achieve load balancing across two default gateways (routers), you must create two virtual IP addresses for two VRRP groups that overlap. Make the first router the primary for virtual router 1 and the backup for virtual router 2. Similarly, make the second router primary for virtual router 2 and backup for virtual router 1.
You can then assign the IP address of virtual router 1 as the default gateway of half of the hosts in the subnet, and assign the IP address of virtual router 2 as the default gateway of the other half of the hosts in the subnet.
Links:
https://forum.networklessons.com/t/vrrp-virtual-router-redundancy-protocol/1151/79?u=lagapides
https://networklessons.com/cisco/ccie-routing-switching/vrrp-virtual-router-redundancy-protocol