It seems like the "flat bar gravel" trend is picking up, and I expect it'll spill over into 650b hybrids with time. (There's really very little difference between flat bar gravel and hybrids, besides knobbier tires and maybe slacker head tube angles.)
Specialized, Trek, and Giant all have carbon fiber 700C hybrids, the S & T ones come in a 1x configuration too. The Trek one looks ideal except for the narrow tire clearance that won't allow 47c tires, and lacks rack mounts - Trek FX 4 Sport Carbon.
Fingers crossed for 2022 model year that someone does a proper high end light 1x 650b hybrid, with road geometry (71+ degree head tube angle) and ideally rack mounts.
https://www.google.com/amp/s/www.cyc...nse-476342/amp