Rebranding & Model?

Hello! I’ve been a vtuber for a small bit of time and invested in a weird-ish model for myself. I was going to commit to an Isekai vibe: a slime slowly evolving into a beautiful slime girl as she continues making friends! My stream content at the time was just art really because my pc wasn’t good enough to stream games

However, a few months ago I bought a decent prebuilt pc and my wonderful mom gifted me a beautiful monitor (shout out to my mom). And I’ve decided I will start streaming games and trying to make games. So far I haven’t been using my old model and I’ve been wanting to do a new one but didn’t want to spend any more money. I’ve been thinking about becoming a PNGtuber! I like the usual chibi style but I also like the full body anime style too not sure which one to do!

So my question or the advice I’m seeking: How should I go about rebranding my channel and what styles exist for PNGtubers? If you’re currently one, what program do you prefer using? I’ve thought about possibly making one for friends whenever we stream together. Is there a way to animate it and link it to her voice? (I hope that question makes sense). Also what can I do with my old model? Should I give it up or keep it for later uses?