I can do voice impressions but it’s not something I enjoy. I do however enjoy mimicking a transatlantic accent and I’ve been fixated on it since I was 15 embarrassingly enough. Most people are familiar with it as the accent used in old films shot in the 1930s for example and I think the history on how it emerged is very interesting. Plus it’s a good accent to use if I want to mess with people.

I can sound exactly like Gollum from LOTR, and I can do a decent Peridot from Steven Universe.

I try a lot of impressions but in practice they end up sounding like some combination between their voice and my "autistic accent"

Responding to my own question guilty! I know. Just fascinated in voice impressions at the moment. I’ve always done them throughout my life. As a kid I could do Cartman pretty well kinda tough now since my voice isn’t as high as when I was a kid of course, but it’s still a voice impression I can attempt. Other ones I can do are Homer Simpson, Peter Griffin, Cleveland Brown, Jimmy Valmer, Kermit the Frog and probably some others I’m forgetting at the moment. For some reason a lot of them are from adult animated shows I have no idea why that’s the case exactly, but might be from the fact I watched those shows a lot so I studied their ways of speaking to do such impressions their voices are also just very notable. I’ve been practicing Stan’s voice which shouldn’t be too difficult considering Cartman and Stan have the same voice actor, but the ways of talking are quite different as you know. Note that I’m no expert and purely just do them for entertainment so they aren’t always 100% the greatest and I likely won’t share them publicly to the internet ever (got to know me IRL to hear them haha) unless I get a funny idea in mind for them and feel confident enough in my abilities to pull it off which I assume won’t be the case for several years.