I have PCOS and am on a normal dose of T. I had the same worries as you about messing with my hormones since it took years for them to stabilise!! But haven’t had any problems so far so I’m glad I didn’t delay starting any longer.
My endocrinologist also had no issues starting me on Testosterone. He wants me to get regular blood tests but that’s the same for all his patients.
I already had a bit of body hair and a bit of a moustache pre-T so timeline wise that is the only thing that seems to have happened quicker than normal (I’m on T 4 months now and already have to shave). I haven’t had any other outwardly noticeable changes except my voice dropping a little.
I got myself a sleeveless hoodie which is decent enough to hide things
Or if small enough you could try tape although can be trial and error. I’ve had some success however only managed to reduce it rather than flatten completely