I want to convert my MTB to gravel, and the main issue for me is the transmission. I plan to completely replace the transmission with 10x2, because it is pretty worn out. However, for me the main question is this: is it possible to use drop bars designed for 10 and 2 speeds respectively on a deore transmission? Cassette M4100 11-42T Rear Derailleur RD-M4120-SGS Chain CN-HG54 Front Derailleur FD-M4100 Bottom Bracket SM-BB52
No, you won't be able to find compatible Shimano drop bar shifters 10-speed Shimano MTB derailleurs. The MTB and road groupsets are not compatible for 10 speed and higher.
I suggest this question for more details about your options for shifters compatible with 10-speed Deore. You also have to think about the compatibility with your brakes, which is not given.
You also won't be able to put Shimano road and GRX cranks on 73 mm bottom brackets and you will have issues with proper fit of your frame. If it fits you with flat bars, it may fit poorly with drop bars.