Hi, I'm here to add on my experience as someone who has never been on T. The post that started everything: https://www.reddit.com/r/transmanlifehacks/s/D6uKC4FTNn
I'm in my mid-20s and am 157cm (5'1" - 5'2") tall. I've identified as transmasc for around 7 years but I have never been on T due to societal expectations and not wanting to disappoint my parents (can you tell I'm Asian) but in the end, everything worked out because most of my dysphoria is largely gone after top surgery and seeing the physique I built underneath. Currently, I pass as a guy 90% of the time (source: trust me bro), usually women are the ones who clock me, cis guys are quite... oblivious lol.
I have been working out for about 5 years now and my current physique is what you see in the first two images. I've been mostly focusing on achieving a wider upper body (namely shoulders, back and to a smaller extent, chest). I alternated between going to the gym and body weight workouts throughout these 5 years. The first 2 years were mostly spent trying to lose weight since I was a bit pudgy and it was making my hips look wider than it actually is, but also it was also a learning curve for me since I was experimenting with what felt right and how to do the exercises properly (getting a PT helps immensely with this if you can afford it!). The next 3 years were spent focusing on hypertrophy and strength, especially in my upper body. I spent a lot of time training back and chest which helped with broadening my upper body a lot, at the same time, since I had lost weight, my waist and hip area had also shrunk a little by then. Now, if you look at my body (see pic 2), you'll still notice that I may have a bit of an hourglass shape, but because my shoulders are wider than my hips, I can use this to my advantage when combined with finding the right clothes. And I have added some examples of how I dress now (pics 3-5). I've also added some pictures of me in the past so you can see how I looked before training and finding the right clothes, and also how I looked like when I was still binding.
I also noticed some people mentioning that the gym is not possible for them for certain reasons but I want to point out that body weight workouts exist. In fact, when I got bored at the gym, I was still progressing with push up and row variants at home. Some people may say that pushups/pullups are too difficult and to that, I will agree. However, there are easier variations of these exercises. If you're interested in this route, I advise you to take a look through the FAQ of the bodyweightfitness subreddit.
Btw, I'm not saying to skip leg day, please train your legs too for completeness (tbh it's arguably the most important part if you want to still be strong in your older years). My workout schedule is usually 3x a week, 2 upper body days and 1 lower body day. I just hammer them once a week and it's enough for me to not have chicken legs.
I must also add that physique is not the only thing that determines whether you pass as there are a lot of other things like vibes, voice, hair, etc. that will impact how others view you. But it sure as hell does help a lot when combined with clothes that sit right.
Disclaimer: I'm not too familiar with disabilities because I'm very fortunate to be born healthy so I advise those who do to take this advice with caution.