I have started to develop an AI voice assistant using python and some other software. I am building it with privacy and security in mind. I am open to contributions. https://github.com/sidgames5/excalibur
Rather than build a new one, consider contributing to one that already exists: like Dicio. It hasn't had an update since 2023-09, but the base is all there. It might be a lot less work for you, and it would help revive a promising project.
I'd recommend looking at the Wyoming/Piper/Rhasspy system. There's some really good minds working on it and it's got a big community behind it already. It's also plug and play with Home Assistant which is awesome. It's the system I use and while I'm still fine tuning it for my use cases it's already pretty great.
I'm experimenting with the Music Assistant add-on but it seems to be early days for that project. Could be awesome though as it combines media libraries from services (e.g. YouTube music) and self-hosted things (e.g. Navidrome) and plugs them into the Home Assistant ecosystem.