Self-esteem is a mess because I need speech and language therapy, but I've had no luck

Hi. I haven't made a forum post on here in a while. I'm an early 20's autistic guy. I've always struggled with communication. I don't like that I have a really monotone voice, because usually people think I'm being blunt when I'm not. I've considered looking into speech and language therapy, but I don't know if maybe the place that I was originally diagnosed at could help me with that? I was diagnosed only a couple of years ago with a classic diagnosis of Autism Spectrum Disorder. I always have to teach myself what I need to say, but I hit a lot of walls with the tone of my voice being the issue. If anyone has any advice or personal experience in trying to work on speech issues, I'd really appreciate it. I have been also trying to look into sign language, but I really want to just be able to be verbal and say things without upsetting anyone. I'm also selectively mute at times, though it still means a lot to me to be able to at least learn tone of voice. Thank you for reading.