Taking T didn't ruin my singing voice, and frankly I'm sick of folks panicking and ignoring the fact that cis boys go through two or three years where their voices are fluctuating and cracking and changing before they settle.
Your voice isn't ruined, it's changing.
If you want to make that transition easier, you gotta keep using it. Sing! Even if your voice cracks in goofy ways. Even if you have trouble placing your voice comfortably. It gets easier, I promise. Get a voice teacher (if you can) who has experience with vocal changes for pubescent cis boys if it's really making you anxious or if you're having a hard time controlling it.
To be clear, I'm not trying to be dismissive of people's emotions, nor am I trying to tell you about your own experience. If you feel something intensely, that's fair and valid. Respectfully, you should unpack that with a therapist or supportive peers.
However, when one of the main TERF tactics against transmascs is convincing trans guys that T makes you Worse in a Variety of Ways, and that you'll be ruining your body if you take it, I am EXTREMELY dubious of how many people online report any part of their body being ruined by T. Sounds suspiciously like TERF shit. And, yes, even Actual Trans People can play into TERF talking points. I'm begging y'all to stop the rampant fearmongering surrounding T.
So, after nearly a year being on T, I'm here to say that YES my voice cracks and YES my voice fluctuates and YES sometimes it feels like I have to relearn everything I knew about being a vocalist, but goddamn if I won't have fun figuring it all out, because I know this is just one stage of the transition I'm going through, and it's worth it.