I do both Insta and Twitter. And Facebook.
Two accounts, one per talent, means twice the work.
It probably depends on what you want to promote: yourself, or your art. But I think you can mix both.
I only have an author account but if ever I decide I'll do some acting again, I'll do all the posting on that one. I post all sorts, not just relating to my writing journey (I probably should post more about writing). Even though my content is varied, I still try gearing it to my branding. I might post a cat pic, or I might post about a writing woe, anything really to show who I am (or want to be seen as). I think variety is better (but I don't know if that's correct) because I suspect followers want to see more than one side of you. Personally, I like to follow those people who have variety in their posts. If someone is only about 'book book book' or 'art art art', I tune out because I get bored or I feel I'm being sold to all the time. I want to see the person behind the book/art. So a Twitter / Insta featuring both your writing as well as your artistry plus posts showing who you are, would work, I think. But that might just be my personal taste and a marketing person might tell me otherwise. Many people are doing well concentrating on just the one talent.
I started following Sylvester Stallone on Insta (don't ask) and he posts all sorts, not just movie stuff. He does inspirational clips. Or he talks about horses. Turns out he's quite an interesting guy.
Maybe decide who and what you want to be then tailor it to that.
On our podcast account (which I do with
@Jonny) our posts are related to the ... well, the podcast and the characters in the story.
It's hard to judge how effective it all is. Having said that Jonny and myself use Twitter, FB and Insta to promote our podcast, and our listenership is going up and up. But not all our listeners follow us our social media. Weirdly, we seem to have a great ton more listeners than social media followers. Still, I think there is a link between finding new listeners and our social media postings. Listener numbers often go up with our increased social m activity (esp the posts we did around Xmas), and even though the listeners don't necessarily start to follow us on twitter, they still come across to Spotify etc to tune in. I think. But Jonny will be able to tell you more about that.
I've found if I follow other writers, they tend to follow me back. Stallone doesn't though. Tcha!
And supporting other podcasts made a big difference because they help promote us in turn. Like everything in life, it's very much a give and take. Support and help others, and they reciprocate.
Anyway, follow us. We'll follow back.
Twitter
My personal one: @Barbara_author
Pod: @GreenCowsPod
Insta
Personal: barbara_writes_books
Podcast: Green_Cows_Dont_Fly