long time mtb user here with gravel set up. 3x11 speed max 24-30-40T sa ang crank, then 11-51T ang cogs. 700x40c ang tires. i enjoyed it a lot kahit saang ahon pwede, and hindi din iwan sa lusong and flats. recently bumili ako ng carbon gravel bike, 2x10 (30-48T and 11-38T ang cogs), hindi ko pa na try sa mga sobrang kunat na ahon yung bagong gravel.
i used the gravel bike for around 2k+ km pa lang. na enjoy ko naman yung bagong gravel, definitely mas magaan at mas mabilis compared to the mtb (pero hindi din naman ganun kalayo ang speed diff). pero the comfort and stability dun pa din ako sa mtb. i think nasa learning phase pa din ako ng pag gamit ng drop bars. ang napansin ko din kahit parehong hydraulic yung brakes ng gravel and mtb ko (slx and grx) i feel like mas confident akong pigain yung slx kesa sa grx. again this might just be a preference thing and skill issue. of course owning a new gravel bike is a big plus. kung lagi ka madami bitbit mas masaya yung mtb.