In a 21st century total war you absolutely would be of use, and likely be drafted/societally pressured to sign up or work in a war-critical industry. I am a fit 22 year old male. So, prime cannon fodder right? Well, in 4 months i will have a degree in industrial engineering, and in 18 months a master's degree in it. So, although I am able to hump a ruck, shoot a gun accurately, pick up a wounded squadmate, etc, I wouldn't be used to the fullest potential of my ability if I were designated to a combat outfit. I would argue that even if I was a rear echelon officer (planning or operations or logistics), it would be a better use of my abilities but still not exactly the most beneficial. No, the place where I would be the most beneficial is in smith and wesson, or Northup Grunman, or Raytheon or General Dynamics as a process engineer, helping iron out inefficiencies in the production line and making sure MORE "beans bullets and bandages" get to the front line at a cheaper cost and at a sufficient quality.

Women would 100% be used in a similar way. I have 50 classmates with the same degree - half are female. They would be Insta-snapped up in wartime. A female doctor or surgeon (of which there are many, including the GP I visit) would be flown to the rear area of the frontlines to help casualties. Etc etc.

Ofc, this is all academic anyways in my opinion. I don't think another total war will or can happen in the history of humankind without a MAD response that just glassifies the entire planet to a radioactive crisp. The only way i see it (a total war like wwii with no nukes involved) as a possibility is if a nuclear defense shield or point defense system comes in to place with a near-100% reliability.