If you’re not climbing super slippery sand (San Diego) or mud, you’re better off with something slick in the middle.
If you’re corrnering on something loose (just a layer or deep-loose), get something with cornering knobs; the miniknob tires (Conti TerraSpeed / G-one Allaround) are OK, but its more than a layer you need knobs (Gone Bite; Terra Trail).
As soon as the ground gets soft, even if it’s smooth, 38c+ under 40psi is going to be faster than less tire.
No matter what anyone says, WTB and Maxxis gravel tires aren’t faster than the rest. I’m not sure if they’re more robust, but I’ve never needed robustness. Conti, Specialized (sworks only), panaracer (non-plus), rene herse (extralight) = speed.