Can't figure out why my computer defaults to the 1gig lan, rather than 40gig for connection to nas

So I was recently gifted some Mellanox 40gig network cards that I installed in my NAS and my desktop and connected with AOC fiber. I gave them both static IP addresses on their own dedicated subnet that’s not used anywhere else in my network. I was able to run iperf3 between both computers, and that worked exactly as expected....