Vyos which edgerouters use

https://docs.vyos.io/en/equuleus/configuration/loadbalancing/index.html

But maybe get something that's not edgerouter

There's mikrotik too

Finally you could look up bonded wan which would give you a 2 Gbps connection...

Did you configure the WANs to distributed and not failover? And did you set the distribution %?

Get a Protectli box with a very good CPU, 4 Ethernet ports, install OPNSense, and have at it.

I'm surprised the UDM Pro cannot route 2x 1 Gbps on two WANs. I thought it was rated higher than that.

Your test might be running into the 1 Gbps limit backplane problem on the built in switch for UDM Pros.

It is impossible to load-balance a single connection when using NAT, as a connection is defined by the IP address. You will get an aggregate 2GBps if there are multiple connections at once. If you want to overcome this limitation you must own your own IP address and purchase transit from two ISPs, but that is expensive and requires networking knowledge.

I went the opnsense route. I have a device configured with WAN LB enabled. When directly connected to the router, it works fine. But when i get behind my udm pro, no internet. Im connected from WAN port on UDM to LAN port on opnsense router. Using 192.168.2.x whereas my udm is 192.168.1.x (255.255.255.0 subnets on both). I have dhcp set up on the opnsense but the udm wont pull an ip. Is there a thing with private ips on the WAN port on UDMs?