It's quite rare that you can conquer a public crowd but you can't deal with mundane every day social situations (I'm sure there are exceptions, it's just a rare combination).
The memorized speech part isn't ideal over time though. To get started that's fine, however it should be a written speech and intentionally improvized after a few experiences with doing it; and then it should be entirely improvized (and a bit shorter) occasionally as well.
And it's structured, so if you are shy about sudden surprise situations, it can be comforting to know what is expected.
It's not a panacea, but it's easy to get started, accessible and designed to help you be more comfortable talking.
Try it, if you want to talk to people more.
That’s what I mean, I believe people like the OP tend to be concerned about daily life, random encounters, completely unstructured situations. Just not sure how much public speaking carries over.
I think it’s quite possible to become a great public speaker, singer, actor or similar, and still be shy in every day life. It seems like largely separate skillsets to me. But I’m no expert.