I had a very bad experience with military onesource. I was going through a rough period and set up to get phone counseling. It was important to me to finish my contract so I was trying to get help through them because I thought my command wouldn't fin out. Unfortunately, during the first session while still just kinda evaluating me, she interpreted "I would never commit suicide but lately I wish I didn't have reasons not to" as I was an threat to myself and without hearing why I felt that way called the ER of the local military hospital. It wasn't until after I got stuck in the psych ward that I opened up about my dysphoria. While I am being discharged because of being diagnosed with GID, I can at least say that have been pretty awesome about everything other than not giving me the option to stay in. While in the military psych ward, they put me in an empty room on the female side rather than put me with male roommates. I didn't think it was necessary but I was surprised that they thought about it. Every Army nurse and doctor in the ward encouraged me to embrace my feminine side and not be ashamed of it instead of trying to keep it bottled up. And instead of discharging me outright, they put me on Limited Duty for 6 months and are paying for me to go to a civilian therapist who has experience with trans clients. My Navy doctor said she did it to make sure I got a good start in therapy and give me a chance to figure things out before going back home. And everyone that has found out in the military since from the other enlisted sailors in my therapy group, my limited duty coordinator, and everyone in the chain of command at my limdu assignment who I felt it would be easier to just tell have been nothing but supportive and have yet to receive any ill will or dirty looks as to why I'm limited duty. I would have preferred to finish my time and dealt with transitioning in a couple years and am pretty offended that they don't want me just because I'd rather be a girl, but overall I am plesantly surprised with how I've been treated.
But the point of my story: Do not trust military one source to not inform your command and if medical finds out you have gender dysphoria, they do not have a choice, there is an instruction that the diagnosis does not allow you to stay in.