I tried this for a couple seasons back in 2017-2019 - went from WTB Resolute/Rene Herse Steilacoom 700cx42/38 to 29x2.25 Schwalbe Rocket Ron and then Thunder Burt - based on the BRR testing. Same drop-bar 29er, just swapped tires and adjusted gearing slightly.
The MTB tires, despite the tests, were never as fast as the gravel tires. I think the diamond pattern and roller diameter vastly understate the real world rolling resistance of most of the MTB tires tested at BRR.
I race a lot of the same guys year after year and my races with MTB tires I was losing minutes to them when prior and after I was hanging til the sprint or dropping some as the race developed. Courses generally 3/5 surface roughness, not buff but not too bad.
I think it’s worthwhile to experiment, but MTB tires for gravel racing, here in the Southeast, were not a benefit for myself.