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.