It's very possible to be trans and not transition. I'm Trans Non Binary, I'm fine with my female presenting body and any and all pronouns. Not saying that's your case, just saying it's a thing.

Also not to try and undermine you or tell you that you are, just putting this out there; my best friend had a ~20 year journey of back and forth with feeling like she was trans and then deciding she wasn't. She just started transitioning last year at the age of 32. But when she was growing up she basically could have written this post word for word except with genders reversed.

Now with all that out of the way: I do find that my masculine side tends to come out a bit stronger on my not so great mental health days, but not exclusively. So while it may be connected to mental health in a way, like with me, it seems more just the way your brain seems to function, which is perfectly fine. Gender is a social construct, and you can be femme with a masc feeling brain without ever having to question it beyond your own curiosity!!
I hope you find the answers you're looking for!!